I know exactly how you feel, friend. Happy to help :)

The regret and heartache is reasonable to feel for a little while - for individuals like him, they often need to do work on themselves on the scale of decades, not months or years. It would be a major lifestyle choice to be the committed, supportive partner/caretaker to someone like that. And it takes major emotional labor and can potentially be dangerous. Scars highly likely.

Feel good about doing what you can to help the person along in their journey while maintaining your own healthy boundaries.

And remember to be compassionate to yourself.

Watch out for the charmers that do the equivalent of love bombing but with charm. Once they have charmed your pants off, the charm stops and the harm starts. That early charm can be a classic abuser trait.

Not all that glitters is gold, and not all that excites is good.

Ask yourself this: would you be willing to lose everything to fall for this man? If not, back away from him and keep your eyes on your goals.