I guess nerve
transfers were done in your son because that is what is done initially. The results of nerve transfers are not immediate and might take up to a year to be clinically manifest and would not equal the non-affected side. It is extremely important therefore that in this interim period you take the help of a physiotherapist so as to achieve proper range of motion of all joints in his affected arm. Depending on the surgery performed, galvanic stimulation to the affected muscles should also continue till there is documented reinnervation of the same.