I don't think you can have the kind of wealth Musk has without it changing who you are. I don't think his worthiness is even worth consideration, if you transferred that wealth to any of us we may handle it better or worse but it would invariably distort our decision making and worldview.
When you change someone's opportunity set to include exercising arbitrary authority over others, their decisions will become more & more domineering. When he decided he was going to take over Twitter and start cracking skulls, he was indulging his worst instincts, and we've seen him slide further into an authoritarian frame of mind.
Not to excuse Musk's actions, but he's a victim here too. I think he's had a rough few years; the pandemic was hard on all of us, and his divorce was presumably quite painful. The other day he was booed by a huge crowd; I don't care who you are, I believe such disdain by so many people has an effect on your mind. And of course his child was harassed immediately after - this seems to have been the last straw to trigger some kind of paranoid episode. It seems like he's convinced that there's a danger to himself and his family, and that he's gone into a really authoritarian headspace.
I think the lesson we should take from this is that no single person should be trusted to have this sort of power.