Is this the right way to discipline a child? My husband thinks it is.?

I need help. I fight with my husband all of the time in regards to my child, his stepson. I have raised my son for the last 8 yrs on my on. He has ADHD. He believes its a discipline problem not ADHD. He doesn't understand. My son is 9 going to be 10 and he makes him do tasks that I believe is actually for adults to do. My husband is a landscaper and after he is done with a job his truck is full of debris. he makes my son go out there and clean out his truck. when he says he can't, he forces him to do it verbally. He may call him names or just make him stay out there until he does it no matter how much he cries. I don't feel it is right. He doesn't spend time with him only when he wants something done for him. He believes child need responsiblity like adults have and he is trying to raise my son the way he is. I think that is wrong. Can someone tell my husband something. He doesn't listen to me. Everyone tells him what he does is wrong but he thinks it right. HELP!