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.
Seems like "more or less" is doing a lot of work in this statement.
I suppose this is what the legal system is for, to settle the dispute within the "more or less" grey area. I would wager this will get settled out of court. But if it makes it all the way to judgement then I will be interested to see if the court sees OpenAI's recent behavior as "more" or "less" in line with the agreements around its founding and initial funding.
"Nonprofit" is just a tax and wind-down designation (the assets in the nonprofit can't be distributed to insiders) - otherwise they operate as run-of-the-mill companies with slightly more disclosure required. Notice the OpenAI nonprofit is just "OpenAI, Inc." -- Musk's suit is akin to an investor writing a check to a robot startup and then suing them if they pivot to AI -- maybe not what he intended but there are other levers to exercise control, except it's even further afield and more like a grant to a startup since nobody can "own" a nonprofit.