I've known the guy for years and I don't think he was serious.
Pretending to be depressed was just his gimmick and having just talked to him a few days ago and how calm he seems in his tweets just reinforces that.
He really did screw up though, hopefully he learned his lesson. At least I hope that is the case.
I see this attitude again and again and I think it's a really dangerous one to hold. The fact is you don't know what's going through the man's head and the fact that you seem to think it's a gimmick is doing no one favors. The first thing you see whenever you hear a news report about a suicide is someone saying "Yeah, I knew him he talked about being depressed but I didn't know he was going to do anything."