Why cant my 16 year old boyfriend ?

well i have been with my boyfriend over a years time now, hes 17 in december. we have been having for 11 month now, and he has never ***! even pre-*** doesn't come that much to be honest. hes worried that he's never going to be able to ***, as he is nearlly 17 so he should of matured by now? he has lots of pubic hair, and some facial hair and some hair on his legs and armpits. is he ever going to be able to ***? also if he hasnt matured yet, will his grow when he does mature? please help! thanks!