Sounds like a pretty weird situation. Obviously his looks (and his health) are important to you, which is not at all a bad thing. See if he'd be willing to take Finasteride(propecia). It's proven very definitely to be safe. If he experiences side effects that persist after a while, you can discontinue the dose and the side-effects should go away.
Finally, I do agree that he should head to the doctor. If he hasn't been to the doctor in years, and he doesn't seem healthy, then it's definitely a good idea.