Ray (Barrie Dunn) is Ricky's father. He's a former truck driver who lived off workman's comp up until season 5.
Prior to the series, Ray was a truck driver. He was a drunk as well, and that eventually ended his trucking career when he crashed into a post office drunk. After the crash, he lost his license and began fraudulently living off workman's comp. For this, he is seen in a wheelchair most of the time, though he can be seen standing on occasion.