Can 100% Mobility Be Regained After Nerve Damage?

My sons friend was in a car accident last week and they had to cut him out of the car. He had no feeling in his extremities. Surgery was performed that day and the next. He can move his arms but cannot open and close his hands or feel anything below his waist. Two days ago they put in a peg tube and a trach since he could not breath on his own after removing the tube from his mouth. They say that his spinal cord was not severed, but he has nerve damage. Can he regain 100% of his mobility.