“Perhaps marijuana has something to do with it.”
You may be right if he is binging on it. However when someone becomes a billionaire then everyone they know personally starts to suck up to them and they cease to get called out on bad behavior and, lacking necessary negative feedback, they behavior becomes more erratic. It is the spoiled child syndrome.
Also marijuana, like any drug affects everyone differently due to their personality, brain chemistry, and other factors. It is like alchohol where two drinks can one man genial and relaxed, another belligerent, another morose, and another goes to sleep.
Any thinking individual should be able to determine if a particular drug is good or bad for them.
He smoked it on a live video stream. That would indicate impaired judgement to me.