I've come across this a few times and never had the solution.
My friend is in his early 20s, a student and lives at home. His DM is early 50s and has been upsetting him through her attitude. According to him, she is constantly commanding him to get a job, do things around the house and stop the computer programming he so loves.
He's got a good business idea but says he feels unsupported and just generally down because she is so unsympathetic. He's joined the gym and sometimes goes with her but otherwise I think they have little in common.
Moving out isn't an option until he finishes his studies. I went through a similar thing with my mum until I moved out...we just got on each others' nerves.
For those of you with young adult DSes...what can they do to make you happy?