at 19 or 90, it is your house, set some boundries if you feel uncomfortable with him coming in at wee hours of the morning.give him a list of chores that you expect him to do.i know being a mother we are adapted to do all for our children that they can do for themselves.i have a 19 yr. old grandson that come homes home at all hrs. of the nite & i just know he is not doing anything wrong.lots of times he & his friends are in HIS yard all nite long working on their cars, lots of times he is at his g.f.'s house & has fell asleep looking at a movie.he works every nite till 8:30.it is just his way of doing things.you have to let go.he gets himself up when he is away at college,he CAN get himself up to go to work if he does not have his mama there to wake him. his job,his consequences. sending prayers for your son that he will stay on the right path.hugs,