Dealing with "I Can't"

I am frustrated dealing with my husband who has both ADD and depression (both treated with meds). He has this "I can't" mentality that drives me nuts. Whenever I need/want him to do somthing that's outside his comfort zone he'll say he can't.

"Honey, can yo help me put the new car seat covers on my car?" "I can't figure them out". They sat for months until the next time i had my car worked on, and my mechanic did if for free. "Honey, can you find out why the lamp isn't working? Does it need a new bulb or is it unplugged?" "I can't move the bookcase to check the plug." (he doesn't have to, he just has to LOOK, but I can't fit in the space where you can see if from. Etc., etc., you get the idea.

The worst is "I can't hang up the clothes, there's no room in the closet." But he won't even think about taking the out of season clothes out and putting them elsewhere.

What happens is I have to do something I'm realy not physically equiped to do (I've got mobility issues) or something it's totally reasonable for him to do. It's one of the biggest frustrations I've ever had being married to someone with ADD. Do any of you have any bright ideas?