First and foremost if you cant hit from both side it doesnt matter obviously...
Let me also say that I think your player needs to show some natural tendency to be able to switch hit. When my son was just old enough to hold one of those big plastic bats sometimes he would pick it up LH and sometimes RH and even sometimes cross handed like Aaron did in his young days. My dad who was a surgeon was truly ambidextrous. He could cut and stitch with either hand. When I put all this together I thought I would try it with him.
My son is a switch hitter and has been since 11. Often times he would go RH when younger b/c, as has been said, he had more power and the team needed him in a power role. I once asked Jack McKeon at a hot stove banquet about hitting from both sides. He said absolutely stick with it. A former AAA mgr told me "I can go to Venezuela and sign all the SH second baseman I could possibly want.. but a SH catcher?.. it really helps his marketability".
We have run into some opposition to it at the HS level.. as mentioned above. We have no opposition to it on his showcase team.
One of my proudest moments was in LL when he hit one out from both sides of the plate in the same game. I will always cherish those HR balls.
ps: and dont forget how much extra work being a switch hitter means in your workout schedule!!!