Your description of the ex-boss, was basically identical to my ex-boss.
He was once an investment banker, focussing on sales for equity derivative products. He then set-up an executive search firm. His charisma was incredible, and he could sell anything to anyone. You just got this amazing feeling that he gave off, and you believed in him.
However he was vain, self-obsessed, and incredibly self-destructive. He did tons of cocaine. His effect on people never lasted: at first they saw this incredible, handsome, charming and charismatic guy and they bought into it. After a while people just got sick of him. I don't think he had any deep or lasting relationships. He'd never stick at anything for much longer than 2-3 years because while he'd be successful at first, based solely on his incredible presence, later it would all fall apart, because he never really delivered. His dealings with people completely lacked integrity.
I've never met anyone quite so charismatic before, but I wouldn't trade places with him. To try and break down what was charismatic about him is hard to say.