As President Barack Obama nears the end of his second term, his hallmark piece of legislation, the Affordable Care Act, has a precarious future ahead of it.

In order to understand just how transformative the law has been for some Americans, HuffPost Rise spoke with two families that have felt the positive impact of the Affordable Care Act firsthand.

HuffPost Rise Zoe had her first open-heart surgery at just 15 hours old.

Stacey Lihn’s daughter Zoe was born with hypoplastic left heart syndrome, a congenital heart defect that required her to have her first open-heart surgery at just 15 hours old. Before the age of 5, Zoe underwent two more open-heart surgeries, and Lihn started coming to terms with a scary realization.

“When we received Zoe’s diagnosis, I had coverage under my employer’s’ plan, but we had a lifetime cap on our policy,” Lihn said. “It’s very expensive. Obviously having three open heart surgeries before the age of 5, she was going to hit that lifetime cap and likely at a very young age.”

Fighting back tears, Lihn described how she considered giving her parents guardianship of Zoe so the little girl could continue to get health coverage.

“And when the Affordable Care Act was passed it was such a relief. It would be affordable and there wasn’t a cap on how much medical care she could receive,” she said, referring to a provision of the law that prohibits the use of lifetime dollar limits on essential health care.

Today, Zoe is a healthy 6-year-old, but her mother, who captivated America with her daughter’s story at the 2012 Democratic National Convention, still fears for her well-being every day.

“I’m extremely concerned about a complete repeal of the Affordable Care Act” she said. “I fear that [Zoe] … at 6 years old, is going to have to be confronted with [the question of] ‘Why am I not being cared for anymore? Why can’t I go to the doctor if I don’t feel good?’ And not being able to protect her in that way and having her realize her own mortality because of an election is terrifying.”

HuffPost Rise Jeff Jeans is now a dedicated supporter of the Affordable Care Act.

Jeff Jeans was another victim of the United States’ complicated health insurance system. In 2011, Jeans’ small real estate business went under, so he lost health insurance coverage. Shortly afterward, he found out he had throat cancer. But without insurance, the cost of treatment was going to be a hurdle.

“I think we lost our insurance in January or February and I lost my voice in September [or] October,” he said. “You know, you don’t think you have cancer. That’s the last thing you probably think of, especially when I was only 49 years old.”

After going more than a year without health insurance, Jeans purchased a pre-existing condition insurance plan through the individual marketplace that was created with Obamacare.

“The very day my policy kicked in, they gave me radiation. They gave me chemotherapy,” he said.

Jeans, who had previously been a staunch conservative and even canvassed for Presidents Ronald Reagan and George H. W. Bush, wasn’t fond of the Affordable Care Act before he received his diagnosis. He’s since had a change of heart.

“When we owned our business and they first passed the Affordable Care Act, I told my wife that we would shut the doors of our business and shutter it before I would comply with this law. And that was the law that ended up saving my life,” he said.

Now a devoted Obamacare supporter, Jeans runs a Facebook group called Obamacare Saved My Life, where he shares health care-related articles and information about the ACA.

Despite stories like these, an Obamacare repeal remains a very real possibility. While repealing and replacing the law will be tough, President-elect Donald Trump has stated that he is dedicated to the cause. And with Republican majorities in both the House and Senate, conservatives may finally have the backing to take down the critical law, a decision that could leave people like Jeans and Lihn in limbo.