My son is 10 and our situation sounds similar to yours! He has no trouble peeing in the potty but to get him to do a #2 I have made a social story, done a potty dance, let him sit on the potty with a book or drawing materials, even let him in the bathroom when I've gone to show him (gross I know) and we have tried rewards! Slowly but surely I think its getting through. P.S. We have him on a potty schedule, every two hours about 10 minutes on the potty with a book and if even a little comes out we act super excited and tell him what a great job he did!

when he goes in his underwear, what do you do with it? For us, when my son would go in his pants we would put it in the toilet and tell him that poopy goes in the potty- not big boy pants. Also, we found that when he would hold it he would end up going when he was relaxed in the bathtub. so we watched him close when he was in the tub and put him on the toilet when we could see that look on his face. If he doesn't go in the tub, does he go to a certain spot in the house or a certain time of day? Another thought i have is cutting a hole in the back of his underwear just to get him to go and eventually fade them away. Bewarem though- even after we thought he 'got it' he still had many accidents until mr. independent consistently went on the toilet.