First of all, DON’T tell him about this site. He will get sick just reading about all this stuff, and even if he weren’t to get these sides upon discontinuation, he may just happen to.
Then tell him that you just realized he was taking Propecia, but he really shouldn’t be. Tell him you have heard it is a dangerous drug, that after years of use can really have bad effects on your body, and that “you have heard, also from doctors, past boyfriends, that finasteride can cause bad effects, and fuck up your prostate.”
Then tell him you love bald men, and think they’re sexy. You won’t care if he’s losing his hair because he’s still hot.
Then hope he NEVER finds this site, but also recovers.
ANd to aid him, set up an appointment with a doc, endocrinologist maybe (preferably one that maybe knows its bad news), and tell him he should just get blood tests before he just quits immediately.
Buy him a year’s supply of Rogaine. If he’s still worried about hair.
Then get him to taper off the stuff over a period of a month or so.
Use it or lose it!
And hope he recovers fine.
If not, soon thereafter get more blood tests, and then a very good stimulation is called the “Clomid stimulation” test.
Get some Clomid (clomiphene citrate) and have him take 25mg before bed each night for three weeks. Then again, hope he recovers!
Good luck mang!