Just because he does harmonies doesn't mean he shouldn't sing solo, the other members of the group sing solo and do harmonies.

The closest i can find to him singing solo is in the performance of love story- jaymi is singing quietly in the background, but JJs voice doesnt sound too bad so I dont know why they haven't let him sing anything....

What, not even the odd line? Rubbish, there is some reasoning behind it, i'm sure he would if he could considering the other three do. He is literally the odd one out.

Wow I just about heard his voice. Wasn't awful.