He was using ranged for the longest time now all he uses is a pool stick even though I keep telling him to use ranged what happened?

Boone did the same thing to me.

My guess is that his gun got shot out of his hand in a battle and he never picked it up. That or the companions are bugged so they randomly run out of INFINITE AMMO. :/

There is a bug that switches ranged off. If you go to your convo wheel and cycle to the ranged twice it should fix it. I had this happen to Boone, and instead of using his shotguns, he used a Mechette ... it was neat seeing him decapitate the Legion guy but him running off the roofg and into a pack of four guys to do it was quite idiotic for a guy supposedly a 1st class sniper.