If he can use a gym or 'Y' then the weight machines that are set up to use both arms are helpful, Start on the lightest weight, then remove the unaffected arm and try to keep going, if needed use the unaffected arm to help move the affected arm. The important thing here is for him to visually see his affected arm working, he has to try to use his brain to move the arm. Having the affected arm just go along for the ride will not produce any benefit except maybe to make sure that the arm has full range of motion. An exercise bike or elliptical with moving arms is also helpful. Talk to his therapists to get stretching exercises to make sure he doesn't get contractures. Rowlands website is very good
http://www.hemiplegiarecovery.com/
Dean
It's a long haul through PT and then some before you can figure out if you can regain the movement but it's worth it! Ask JR - he had entire left side paralysis and was told by VA Rehab (after 5 months of rehab) that they didn't know of anything else that would help him. After 4 months on an eVO motor assisted stationary cycle he began regaining movement. He's been on it for over a year and is back to work. He is still doing his own therapy and adjusting how he does it to get the outcome he wants. See Assistive Therapy Solutions eVO video 3 on the front page. You have to keep moving!