The Wantagh founder of a veterans’ group pleaded guilty Thursday to stealing close to $90,000 from a 71-year-old veteran suffering from PTSD and dementia, the Suffolk County district attorney’s office said.

State Supreme Court Justice Fernando Camacho told John J. Lynch, 76, he could avoid jail time if he repays the victim and forfeits a Porsche he bought with the veteran’s money, prosecutors said.

He pleaded guilty to two counts of grand larceny for stealing $87,260 between February 2013, and February 2014, by having the victim write checks payable to him or his business, J. Lynch Staffing.

Lynch had started Suffolk County United Veterans, acted as its executive director and operated the John J. Lynch Veterans Men’s Shelter in Yaphank.

Lynch’s attorney could not be immediately early reached Thursday night.

District Attorney Thomas Spota said there was also evidence that Lynch had the victim pay his American Express bills.

advertisement | advertise on newsday

“The defendant’s crimes were unconscionable,” Spota said in a statement. “Our investigation found that he exploited a vulnerable fellow veteran who is suffering from post-traumatic stress disorder and trying to cope with severe memory and confusion issues.”

Lynch is expected to be sentenced in October.