Obviously money doesn't buy happiness. It can certainly put you in situations where you may be more likely to experience happy moments (cruises, vacations, etc), but it doesn't really fulfill most people.
Rich and famous people can obviously be depressed. I mean, we lost Robin Williams due to depression. Arguably half the meds Heath Ledger was on dealt with depression. Being rich and famous doesn't magically mean much for your mental health.
Of course, a lot of his complaints sounds more or less like he needs a job again, or a massive hobby. Yes, partying with people who honestly don't give two craps about you can get old - even us "plebs" deal with that if you happen to be a frequent bar goer.
Waiting for your friends who have to work their arses off to have time to hang out does suck - but see, it's because he has all this free time and he doesn't know what to do with it, you know? He probably doesn't want the attention he would get for forming a new company and making a new game, but he also doesn't want to sit around every day doing pretty much nothing, and then partying at night with people that don't care about him, simply because he pretty much has nothing else to do.
He needs to find a new purpose in life. Before, that purpose was probably to make enough money making something of his own to live on. Now that he's well past that, he needs to find a new daily time filler that isn't self destructive.