I started on acoustic, because I was listening to that type of music in the 60s. I later obtained a hollow body electric as my tastes changed, but now play mostly acoustic.
My son started on a solid body electric, because he was a blues/rock fan. He later played punk through high school and now plays mostly bluegrass mandolin. The Les Paul sometimes stays in the case for months at a time, but he can't bring himself to get rid of it.
I think the point I'm trying to make(I'm never too sure) is that I feel he should get the instrument that will motivate him. Also, a cheap electric (Strat clone) is often easier to play than a cheap acoustic. If you go for acoustic, get a reasonably good one.