The thing is, if he doesn't ask he'll never know. But according to him it's better not knowing? How does it feel mister? Not knowing? Not having any finality?
Check this, here's the scenarios that can happen when you ask:
a) She says yes, but your friend isn't very happy about it
b) She says yes, and your friend couldn't give a **** and is happy for you two
c) She says no, your friend doesn't find out and you're still bro's
d) She says no, your friend finds out (either from her or someone else) and is pissed off with you
e) She says no, your friend finds out (either from her or someone else) and is NOT pissed off with you
f) She says yes, but after a couple of months of hot sex, she dumps you because you were just her rebound guy
g) She says yes, you have rumpety dumpety for a couple of months, she dumps you because you seem indecisive and unsure about what you should do with your life and admits she already had a couple of rebounds before you and that she'd rather have them than you.
etc etc etc
But no, it's okay, go procrastinate some more. Go cry in your emo corner (still, cutting yourself is lame btw) and never find out if this girl would have actually made you happy and things could work out or not.
In fact, I recommend you should perhaps avoid going out altogether, you never know what kind of decisions you have to make in the real world hey... just now someone asks you to pick a number between 1 and 10 and you're scared to because it might be the wrong number.
And I end with my, "Grow a pair" slogan...