Help for computer addiction.

[CarnivorousJelly]

Does he have any multiplayer games on his computer?
Ask if you can play them with him to socialize, slowly integrate other elements ("hey, wanna grab pizza/more friends and play mariokart?").

People's interests change over years - and you're comparing now to five years ago; that's a long time. Also, you haven't specified but, maybe he's got something else going on in life right now and computer's just the best escape for him. Best thing to do in that case would be his friend. Don't necessarily "enable" his computer habits, but don't push him too hard or he'll push you away instead.