My D did the same thing when we lived together. I believe she continues to stay in her room. My niece and nephew do the same thing, stay in their rooms and play video games, or chat on the phone. I stopped worrying about it. Actually my D yesterday told me she wants a car and will be taking her drivers test? really, a major change from her. So keep an eye on him but don't let it consume you. It is most likely a phase, different from what our age group is used too. And most of the teenagers I work with do the same.
M 53 D 20 Separated 6/22/11 moved out 10/24 Together 26 yrs Married 16 W Filed for D 7/21/11 Served 9/6/11 D final 8/28/12
“Failure is not fatal, but failure to change might be.”