That’s a tough situation because rigid thinking with autism is likely at play. A system of do these things to get privileges often works for those with very concrete thinking. Since that’s not working, I’d try tackling it in a different way.
Try having conversations about how a family is a community and a community can only succeed when every member does their part. If parents have to take on more of the tasks, then parents don’t have time to do things kids want (where do you take him or what do you do for him that he wouldn’t want to stop?).
He will never have intrinsic motivation for something he’s not interested in with an ADHD brain. You have to make the task interesting or add an extrinsic motivator that works for him.
ADDitude Community Moderator, Parenting ADHD Coach & Author, Mom to teen w/ ADHD, LDs, and autism