While my parents are sleeping, I'm going to steal their wallets.
That sounds like a terrible idea. Would you really betray your parents trust by stealing from them?
They weren't very good parents.
I'm sorry they were bad parents. But it's always wrong to steal. And you could end up in trouble with the law if you do.
It's too late, I already got their stuff.
Well you can likely expect to be yelled at and punished once they find out. However if you return what you took and apologize they might be willing to forgive you. You'll have to work to earn back their trust though.