@ehBeth,
Agreeing with ehBeth.
You knew their relationship before you married, why do you think it would be any different?
You aren't going to change her, and you don't want to get between the 2 of them, unless you want her to become a permanent point of contention with him for your entire marriage. He likes the way his mother treats him apparantly. They are fine with the arrangement, it's you with the issue.
You put 2 stipulations on moving, finding a place of your own AND her getting on her feet.
What's her and his incentive for that? None. She gets to live with her son and take care of him, and he gets to live with his mom. Are you both living with her in Her home? What suddenly happened with you married that she can't support herself?
Also, it's not like you don't cater to him as well. What does working the night shift and and needing extra time to sleep have to do with each other? Do you work as well? If so, do you need someone to pack your lunch for you?
Getting a little off track, I was interested in that comment "I cook for him when he is hungry" Yeah, ok. Does his hunger happen to coincide with agreed upon meal times? Or are you a short order cook whenever he wants something? Does he know how a stove works? I sort of doubt it.