Replies to 'Setting Boundaries'

My stepson is 13yrs old. He doesn't take care of anything he owns let alone anyone elses things or feelings. We got him a cat and he gets mad at me when I tell him that he needs to clean the cat litter or give the cat food. He says to me " Oh my God! I fed the cat last week!" I really like the cat and I don't want to get rid of it. When he eats he uses his fingers and then wipes them on the furniture or his clothes. We recently bought him a desk so that he can have a computer (without Internet) in his room, so we told him to clean up his room and move things around the way he wants. He asked me to help him, but every time I help him I end up bossing him around and then doing everything myself. My husband gets upset when I yell at our son, but he does not listen to me any other way. My husband has spoiled him through the years and now his son does not even listen to him. It's like we are just wasting his time for him to do what ever he wants. I am getting frustrated at my husband and we are starting to fight over what to do about our son.  When we punish him for the way he is acting he just sits there like oh well or sometimes just starts crying. He knows what he is doing is wrong. We both love our son. We really want him to care about things and/or do things without having to explain everything to him. What can we do as Parents, so that our son will do things he should be doing on his own? And caring about the things he has instead of taking them for granted?