This sounds familiar - but I will say, at least you're making an effort to discuss the issue and gather feedback before taking any actions, which is a good thing, most companies would distance them, get them to quit.

If you want to help him resolve his issues, you're going to have to become involved in them. Time, listening to him, never breaking his trust - no matter your good intentions - and taking that 3am phone call of dispair and offering hope.

If you cannot do this, do not try. Does it really mean that much to you? Or is it an inconvenience to your "now"?

Suggest a sabatical and let him figure it out in his own time.