In my experience ... they have learned to activate that charm when among other people/in the spotlight.

Being on their own, they have their dark moments, too.

That, and he was already wealthy by the point the OP ran into him. I’m still poor and every additional dollar I receive increases my happiness immensely. Dollars buy dignity and he had no restraints in life at all financially.

This works less and less as you earn more. At some dozens/dollars a day (I don't even mean homeless, I mean when you pay the rent and only have some crumbs left - I have a lot of experience living this way) every additional dollar makes you happier. As soon as all your basic needs are covered you (I) lose all the emotional interest in money and only feel interested in experiences, free time and increased security.

Taking in to account he was drunk he must be real

Umm, no. Plenty of people have outward personas that they can maintain through extreme intoxication.

Guy Burgess was well known when a British diplomat for protracted alcohol binges accompanied by all sorts of poor decision-making, but he never let slip that he was a Soviet spy.

Not to mention Sasha Baron Cohen passing out from wine and waking up in character as Ali G - at least anecdotally