Given that SpaceX is a private company, where Musk owns the vast majority of voting rights, I'm not sure what can be done here. The same goes for Twitter, and I doubt Musk is stupid enough to have bylaws in a company he bought 12 months ago that would oust him for drug abuse (although I would fucking love it!)
Tesla, though, is only 21% owned by Musk (assuming Wikipedia is up to date). While it's tight, I imagine the board could request he take a drug test, and if he refuses/fails, call a vote to remove him. Given that Tesla execs have been worried about his unhinged behaviour for years, it could be the blessing they've been hoping for.
I think the issue is that SpaceX has government contracts. NASA and the military are probably more likely to be authoritarian about drug use among their contractors. He got in some hot water for smoking a joint in a Joe Rogan episode a few years ago too.
I think it's ridiculous of course. Let people do drugs. If he becomes incompetent then oust him for incompetence. Don't bring drug dogs in, especially since they're really only going to find low-level employees self-medicating while the execs weasel around it.
The drug-use aspect is irrelevant here. I don't care if govt contractors are using drugs, as long as their work is effective. And the Falcon 9 rockets are unmatched. And the Starship prototypes are groundbreaking.
I could make some moral complaints about Musk as a military contractor and grifter, but specifically regarding SpaceX and drug use... I 100% support it. I mean, he should get a grip, but drug use is not where I want the govt to focus.
Nothing, and nothing needs to be done. It's his company, he can run it how he wants and that will result in how successful it is. Personally I wouldn't be anywhere near him and unless I had a dire need not to, I'd quit working for whatever company he owns and find somewhere more sane to spend my time