I started losing hair very aggressively around his age, 15, but it got very visible at 16. I am now 25 and a stabilized NW3-4 because of using finasteride and minoxidil, not even religiously. I was on and off the stuff for 6 months at a time until 22 when I started using it every day. I would use it for half a year and then not use it for the next half, which is why I am not in a better NW pattern now, but also why i'm not NW6-7.
I would not tell him to give up, I would tell him get on fin and minoxidil and then think of an HT. I could have given up too since my hair started falling as far back as 13 years old, but I don't count it because I was an NW0, I count it really starting at 16 when I am sure I had lost 50% already. I didn't give up. Sure my hair loss is bad, but I halted/slowed it down to the point that an HT would get me where I want to be.
Giving up should not be an option for a young guy like him. I remember seeking advice from my dad, mom, and family members, "shave you head", useless advice, primitive. Thanks to the information I found around 3-4 hair loss forums, I found a way to battle hair loss.