Kindly do the manual muscle testing of the muscles around his shoulder and shoulder girdle. Give assisted ROM exercises to muscles which have strenght of grade 2 and give graded exercises to muscles which have power or strenght of grade 3 or above. Give strenghtening exercises to muscles which has power around normal grade. You don't need to give electrical stimulation to muscles which have power or strength of grade 2 or above or muscles which show signs of sufficient activity or movement. However, you may warm up the muscles before exercise by giving Infra red rays for 20 -30 minutes to get a better response from prepared or warmed muscles. Also keep on doing the regular Passive ROM exercises in muscles or joints of upper limb to preserve muscle and joint ROM and elastibility and tp prevent the joint stiffness. Use splints only in those joints where there is sufficient muscle imbalance or impairment of the quality of movement of function. Just feed back us your results.