I' m 20 and have ADHD. My mother could relate to you because I had a hard time doing my homework and chores, as well ( I still do.) My mother finally gave up helping me with my howework and got me tutor; it was very beneficial becasue she didn't stress, and more importantly she didn't stress me out even more. I had many tutors, but the one that helped me the most was a neighbor. She was a college student so it didn't cost that much. She was helpful beacuse would make silly rhymes and teach me new and exciting ways to memorize things like multiplication. She was also very patient.
I understand exactly how your son feels. With help, patience, and encouragement he will eventually find learning exciting. Educational videos, interactive game and kits will help him as well. Making homework more interesting will help ease the stress for him. Good Luck!!