He's not happy, but that's got little/nothing to do with his money. He's doing the same things and experiencing the same consequences as a lot of people who fall into the extreme-right. He alianted his family, he's in trouble at work and he's blaming everyone and everything but himself. Only difference between him and the qanon conspiracy-brain who got fired from the plant in some small town for saying racist shit on Facebook is that Elon's wealth and public status means his life falling apart is a public spectacle instead of a private one. That, and the fact that his meltdown impacts a lot more people.

Money actually does buy happiness for most people (up to about $75k USD annually, at which point the correlation fades). I suspect that happiness is a direct result of not feeling like you're 1 sick day from homelessness, but I don't think the data is there to support why yet.

Edit: $75k, not 7k