Goose-
I feel your son's pain. I started loosing my hair at 22. I started noticing a thin spot on my crown in the begining of the year(feb/march96). I saw alot of hair falling out over the next few months. by the end of the year(nov/dec96) I had a 2 inch bald spot. I started using rogaine/monixidil at that time. I used it for four months, I tought it wasn't doing anything plus I hated putting on everyday!!!! I stopped using it apr/may97. I noticed by the middle of june my crown bald spot was getting shinnier and bigger! a few months later my hair line started to show signs of "see through". I tried every snake oil in this country(nioxin, ?nizoral?, thickening shampoos, AVAcore, saw palmetto/vitamins) none worked. I moved to the Philippines and tried the what they had out there, none worked. by march 99 I decide to try FINASTERIDE(Propecia/Proscar) used it for a year expecting to see new growth but didn't get what I wanted, I did notice not as much was falling out after 3-6 months of using it. My DHT must have been on the warpath cause a couple of months after stopping Propecia I had handfulls of hair coming out in the shower. My roomates used to tease me by collecting the hairs after I showered and taping them together, then leaving them on the coffee table with a note "these belong to you".
My point is this - your son can use Propecia and Minoxidil. Do not expect a dramatic return of the hair line or thickness on the crown. The best he can do is stop the advancement of balding. If I would have stuck with the products and followed thier directions when I used them I would not have had so much loss. Minoxidil can stinulate hair follicles to grow, thier survival dependes on continuing the use of the product- INDEFINITELY!!! Procpecia(FINASTERIDE)/Proscar can slow and eventually stop the hair from falling out by reducing DHT production. Using the products is going to be costly and always indefinitely, that may be why the doctor told you to do nothing. I personally would love to be at those first stages of hair loss and restart the treatments. I would not have gone through all the heartache, I spent more money on "snake oils" than I would have on a solid regimen of Minoxidil & Propecia. Alot of people don't like the thought of treatment for the rest of your life, but the fact is there is no cure for baldness, it is progressive, and there are only ways around it. Now I am 31 and I have just had HT done 2 days ago, it is a little painful but the benefits will be awesome. And even with the HT I still am going to use Minoxidil/Propecia to combat mother nature(DHT). If you want to show your son what to expect (or something like it) if he does nothing, then look at my photo album.
http://www.hairrestorationnetwork.com/eve/showthread.php?t=
In the mean time your son can use some cover up products like TOPIK. These are day to day temporary quick fixes. They wash out in the shower. So far in my opinion to stop balding - stop DHT with Propecia, try to stimulate hair follicles with Minoxidil. Look around this forum and research HT doctors, if that is the route your son decides to take, there are many good ones talked about here! Best of luck!