Zyg's got it right. Most guys who aren't competing average 4IUs a day (5 on/2 off). I bump to 6IUs a day (5 on/2 off) when I have extra but I start feeling sides at 6IUs a day. Benefits are great if you do a consistent dose for an extended period of time. Don't expect it to do much for you unless you do at least a three month cycle. Also he's not going to see a whole lot of results if he's young to begin with. This stuff is most effective for guys 30 and up.
A typical three month cycle would look something like this:
Month one -- 4IU ed (5 days on/2 days off per week)
Month two -- 6IU ed (5 days on/2 days off per week)
Month three -- 8IU ed (5 days on/2 days off per week)
Your friend would need at least 3 kits of the Serono/Serostim 126IU for a three month cycle like that.
The two days off per week accomplishes two things. First it cuts back on the amount of GH you need, that's good because it's expensive. Secondly, and most importantly, the time off allows your pituitary gland to upregulate and continue natural GH production.
**Just saw that he competes. You posted while I was typing. That's a whole different thing and it depends on so many things. His age, weight, number of cycles, experience, etc. His trainer would be the best person to advise him.**