Of course, this all depends on the investment details specified in a contract and the relevant law, both of which I am not familiar with.
Musk pledged donating orders of magnitude more to OpenAI when he wanted to take over the organization, and reneged on his pledge when the takeover failed and instead went the "fox and the grapes" path of accusing OpenAI of being a failure.
It took Microsoft injecting billions in funding to get OpenAI to be where it is today.
It's pathetic how Elon Musk is now complaining his insignificant contribution granted him a stake in the organization's output when we look back at reality and see it contrast with his claims.