To those suggesting not to shave it: do you remember what those little scraggly pseudo-staches looked like at 14?!
I use a razor and shaving cream because I have very thick facial hair and I have never been able to find an electric shaver that didn't rip my face to shreds and hurt like hell. At 14, I think I used a razor with no shaving cream to do the quick little clean up on my lip. At whatever point it started to irritate my skin is when I added shaving cream.
If the electric razor is the way you get him interested in it then go for it, but he should know how to and try to use a regular razor also. IMO it is much less painful and kind of a satisfying, manly experience.