SALT LAKE CITY — President Thomas S. Monson's legendary and prodigious memory deteriorated at the end of his life, creating an ironic challenge for a man revered as a prophet by 16 million Mormons.

"He was a man who believed in creating memories," his daughter Ann Monson Dibb said Friday, "and that's why it was so sad that he had this belief and knowledge his whole life — that 'God gave us memories that we might have June roses in the December of our lives' — and then his memories were taken.

"This was Tom Monson's test."

A large, energetic man with a still larger-than-life presence and a fixture in LDS Church leadership for more than half a century, President Monson died peacefully Tuesday night in Salt Lake City at age 90 of causes incident to age. He spent the past decade as the president of The Church of Jesus Christ of Latter-day Saints and a total of 54 years in the church's First Presidency and Quorum of the Twelve Apostles.

Dibb, one of his three children, described her father as a unique, "whirlwind of a man" during a poignant, exclusive interview on Friday but said that even as his memory and health worsened, she made sure he could continue to do what he had done throughout his life — visit the sick, the lonely and those who needed lifting.

"Tom Monson needed that because it made him happy," said Dibb, who served as a counselor in the church's Young Women general presidency from 2008-13. "It was core to him. ... The most valuable things I did with my dad in the end were making personal visits. There is such a beauty in those moments, and also a power in those moments, because he made a difference."

Striking memory

Dibb provided the back story to the legend that President Monson memorized his talks.

As a 12- or 13-year-old boy in a congregation on the west side of Salt Lake City, he prepared a talk and read it in church. Afterward, a local priesthood leader told him the talk was wonderful but that next time, he needed to memorize it.

"Every talk he gave after that was memorized," Dibb said, "up until he joined the First Presidency (in 1985) and had to give multiple talks at each general conference."

Once, when church leaders couldn't ship materials to members behind the Iron Curtain, he learned by heart the entire handbook of instructions for leaders. Then he traveled to East Germany and began to type it out, only to find a copy of a handbook in the room.

However, by the end of his life, he struggled to remember he had just told a story or given a talk. He began to repeat himself, even to restart a talk on occasion.

"His memory was incredible through the years, and he lost that ability," Dibb said. "It hurt to see. It hurt because it would hurt him to be recognized that way."

A church spokesman said in April 2015 that President Monson was feeling the effects of advancing age. He cut his speaking load from four talks to two at the faith's global general conference. That October, he visibly weakened during another conference talk. He began to deliver shorter addresses, but that December, another church leader said that President Monson's short-term memory wasn't what it once was.

In April 2017, President Monson spoke at general conference for the final time. He was hospitalized the following day and did not appear publicly again. His two counselors in the First Presidency, along with the Quorum of the Twelve Apostles, managed the day-to-day affairs of the church, displaying the redundancy built into the LDS Church's leadership system, which ensures continuity when a church president is ill, incapacitated or dies.

During this time, Dibb helped President Monson so he could continue to speak at funerals, visit the sick and be helpful.

Good cheer

His failing health — he had a pacemaker — and declining memory were real challenges for him, Dibb said.

"His service and his work was who he was. It was (his) identity. It was also how he managed his energy. So as various things were taken away in his ability to do things, it became difficult for him to know what he should do next, because that was his life and that was who he was and that's what brought him joy."

She realized it was essential for him to continue to serve.

"It's how he could be of good cheer," Dibb said. "That was extremely important to him, to have that as a part of who he was. ...

"And then afterwards, he was happy. He was whistling for the short time he could remember the experience. It calmed him within him, knowing that he had done something good for someone else."

It also calmed those he visited. She said caregivers told her that those he saw regularly felt better and did better for as much as a week after he visited. And the effort cheered her, too.

Lessons learned

Near the end of his life, President Monson told Dibb a story she hadn't heard. As a young boy trying to raise money to buy pigeons, he did work for his great aunts and accepted money.

His father, G. Spencer Monson, reprimanded his son: "I am disappointed in you, Tommy."

The next time President Monson visited his great aunts, "he gave the money back and did even more work," Dibb said.

He told his daughter, "Sometimes the greatest lessons are the mistakes you make."

In a video made of President Monson’s life soon after he became the LDS Church president, he is pictured pointing his finger and explaining, "The lesson was not lost on me."

Dibb said the clip exemplified the way her father responded to his father’s reproof after accepting money for acts that should have been offered as service and for so much more.

"It wasn’t lost on him," Dibb said. "He was incredible as to observing a situation, recognizing what needed to be done or changed and then doing it. … He only needed to learn a lesson once."

But that didn’t mean President Monson did not enjoy himself.

"He was having a great time all along the way," she said.

Motivated minister

Still, though her father could be laughing and telling stories during a visit, if he detected a concern or worry, his focus would completely change. He would stop talking and listen and determine "what can I do to help."

President Monson treated others the way he would want to be treated himself, Dibb said. He recognized "how people tick. He knew everyone wanted to feel acknowledged and safe and helped."

President Monson visited friends who were at the end of their life — friends who were once powerful, but now infirm. "He would go and take their hand…," Dibb said. "He would talk to them as though they were at their finest moment."

Dibb said she felt her father often reached out to others simply because he knew it "would be a nice thing to do."

He did what he thought Jesus Christ would do, she said.

After the fact, they sometimes learned of the miracles or answered prayers as a result of his service.

"Who did he look to as his example? It was the Savior," she said. "The Savior was a good teacher. He was forgiving. He was loving. He was perceptive as to what a need might be. He blessed and healed and taught."

Dibb saw a lot of those traits in her father. "They were spiritual gifts that were made more manifest because the lesson was not lost on Tom Monson."

Frances and Ann

A constant in President Monson’s life was his wife, Sister Frances B. Monson.

Dibb said her mother, at times, would step back. More important, when necessary, she would step forward and say, "Now, Tom."

"She would encourage, she would listen and she would enable," Dibb said. "She was powerful in her quiet manner."

Dibb said her mother knew how many things were upon her father’s shoulders. "She always wanted to provide a place where he could come home, where he could relax, where he could do what he needed to do in order to be prepared for the next day and put some of those concerns aside and be refreshed."

She did not complain. But she did encourage. Dibb said her mother would ask, "'Have you thought about these things? Have you considered these things?' Many times he hadn’t."

Often that left her with the mundane tasks of running a home.

Dibb said everything began when her father walked in the door. "He always had a brief case and it was always full," she said, noting that he would ring the door bell several times as he walked in "almost like an announcement that he was home."

There were always things her father was concerned with.

"He was always mindful. He was a means by which individual’s prayers could be answered if he listened, if he looked around and perceived who might need help or a friendly hello. It was just all wrapped up in a 'whirlwind of a man.'"

In the year 2000, Frances Monson suffered a terrible fall. "She wasn’t able to do what she was able to do before."

Afterward, much of the support President Monson once received from his wife, he received from Dibb. That intensified on May 17, 2013, when President Monson lost his wife and then again when he was no longer able to participate in the daily administrative activities of the church. Dibb and her father watched reruns of the Lawrence Welk Show and took long rides. They also found ways to serve and visit those in need.

Because of his boundless energy, helping her father was tiring, Dibb said. "When my dad didn’t have my mother, I had learned enough from my mother, that I could step forward and do it."

Dibb compared her father at the end of his life to a car with 400,000 miles on it.

"He was full steam ahead all his whole life, and he was worn out. They weren't making parts any more for Tom Monson."