JACKSONVILLE, Fla. – The sister of a man who killed his wife and then himself in a San Souci home Wednesday night said he did it because he couldn't stand to see his wife suffer any longer.

Officers found the couple dead in their home on Goltare Drive about 3:30 p.m. when a man called 911 to report that he had shot his wife and was prepared to take his own life.

The Jacksonville Sheriff's Office won't identify the victims, but family members said John and Gwendolyn Thombleson died in the home. The husband's sister said after the wife had surgery eight months ago, her health began declining rapidly and she developed several health conditions, including dementia.

The medical bills were piling up, and neighbors told News4Jax that John Thombleson had said their insurance was expiring, leaving them no way to pay for the mounting expenses.

According to police, officers sent to the home made numerous attempts to contact the people inside but the attempts were unsuccessful.

Eventually, members of the SWAT team entered the home, finding the man and woman in a bedroom.

The couple were high school sweethearts and had been married 47 years. John Thombleson was retired and Gwendolyn Thombleson worked for the school district.

This was not a domestic dispute, according to the family. They said they tried to help as much as they could during the time when the wife's health was deteriorating.

Family members called this a mercy killing and said that John Thombleson was motivated by his love for his wife.

The neighbor who lives across the street said the last time he spoke with John Thombleson, the conversation was about the couple potentially losing their home because of their mounting medical bills.

Drazen Klacer, another neighbor, said he never noticed any red flags.

“He was nice guy, older guy, ready to retire," Klacer said.

Lisa Veres, a third neighbor, was shocked to hear about what happened.

"You don’t hear of anything like this happening in this neighborhood," Veres said. "We’ve lived here for so long and my husband’s family has lived here for so long, and everybody is just so quiet and so sweet."

The family is planning the funeral arrangements.