Too relevant to be less than a comment:
"rubber ducking" (a bit of psychological phenomenon)
An opinion, that vocally presenting your own counsel leads to more "in tune" outcomes. You already know what needs to be done, but the struggle is real.
"should I do this...or that?". we've all faced this before, and especially when we face very real risk and reward. You've said that this individual is on top of his game, the world is his oyster, and handsome to boot. that's the result of skill, determination, hard work, and dedication, and good grooming (plus a good roll of the dice). Who can he relate to? He gives himself guidance, pep talks, and keeps himself on the right track. He sounds very responsible. He likely stops when approached because, well, since you're asking in concern, of course it seems "weird" to do such a thing. The proof of why he stops is right here. would you continue talking to yourself while others gather?
Why not ask him directly if he is alright, if he needs help with something, and is there anything you can do to assist? (gently). He sounds logical (and I suspect honest), and would likely accept help (maybe emotionally), or just realise on his own that he's dealing with things his own way, and then just by asking, you've helped him move along.
In software engineering, rubber duck debugging or rubber ducking is a method of debugging code. The name is a reference to a story in the book The Pragmatic Programmer in which a programmer would carry around a rubber duck and debug their code by forcing themselves to explain it, line-by-line, to the duck. Many other terms exist for this technique, often involving different inanimate objects.
Many programmers have had the experience of explaining a programming problem to someone else, possibly even to someone who knows nothing about programming, and then hitting upon the solution in the process of explaining the problem. In describing what the code is supposed to do and observing what it actually does, any incongruity between these two becomes apparent. More generally, teaching a subject forces its evaluation from different perspectives and can provide a deeper understanding. By using an inanimate object, the programmer can try to accomplish this without having to interrupt anyone else.