Hi, Thanks for posting in HCM. I understand your concern. If a person with Duchnee Muscular Dystrophy is unable to reach his arms to masturbate, then it would be very difficult to do it on his own. He can do it with assistance of someone or with some props which can help him to contact with his genitals that can be further stimulated. Kindly see what best can be done which would ease him to do the activity. Hope the information provided would be helpful. All the best.