James Yeckel, 54, was sentenced Monday immediately after he entered his plea to two counts of third-degree murder, the Pittsburgh Tribune-Review reported.
The bodies of Carol and James Yeckel Sr., both 74, were found in September 2011 in their home in West Deer about 15 miles north of Pittsburgh. Both had been shot.
Yeckel was diagnosed as a schizophrenic in 1994. His sister, Deborah Rees, told police he had a pattern of disappearing for months or years at a time and then returning home to live with his parents.
Rees said her brother came home for the last time in August 2011. She said her mother was frightened of him and worried about the way he was acting, including watching television with the sound turned so low it was inaudible and saying he could talk to animals.
Relatives cried as Yeckel apologized during Monday's hearing.
"I wish he would have accepted the help offered to him many times throughout the years," his sister-in-law, Jane Yeckel of Baldwin, said after the sentencing. "This would have never happened."