What do you do?..? About what? ..Him?... nothing... get on about life and wait for him to decide he wants to be a more productive member of the family.
Try not to sit around wringing your hands worrying about him or his behavior. You have no control over that stuff. Only he and he alone can make the decisions and take the actions that will better his life experience.
You can keep yourself busy in the house, at work, in the yard, with a hobby, visiting friends, hiking, biking, walking in the park, read good books, take a class, learn a language, look up your genealogy online, the list is endless... there are thousands of things you can do with your time. Things that will keep your mind busy, and focused on something other than your son.
I know it's hard. My son is being difficult too. Different reasons, different behavior, but it still sucks. I have let him go about his life while I go about mine. When I start getting upset about the situation I remind myself that his life is his to lead... when my son is ready to be the respectful young man I know he was raised to be, I will be here ready to rebuild our relationship. Until then we just leave each other alone.
*hugs*