lol,
Well again depending on where you land but yeah, he could go clubbing and drink since he's over 18 yrs old and as a result get laid

Just read the short article quote (CBS) on hoopshype rumors which mentioned him earning 800k and a million in endorsements. I do not see that happening. He'll be very lucky to receive 800k, he'd be lucky to receive half that since he'll essentially be a rental for one year who will need a lot of work. Endorsements would again be an investment of nike or adidas for when he returns to the states as Europeans don't get that much in endorsements.
Salaries are usually net though, so after taxes. That combined with next to none living expanses and that's a pretty sweet deal.
He should sign with an agent as soon as he doesn't go to college, to find out which international teams are interested. Might be wise to not be the only american on the roster to ease the transition and to make sure the agent has a buyout for the 2nd yr in the contract equal to the max amount buyout NBA teams are allowed to offer.