Can Suit Therapy Help In Case Of Cerebral Palsy?

hi my nephew was born with cerebral palsy, he was not able to sit , nor the neck would not stay straight, he is 13 years old, he can sit, the neck is pretty good, straight, but still cannot stand on his own, so he needs support even to move his body, in case he wants to sit, mostly now hands and back support and the feet are totally has no suuport of its own, the parents are doing suit therepy in detroit, will any of these and the constant physical therepy he is goin thru will help him be indepent? he is all good in his brain and intelligence. is there a cure?