J.
Hi, I am J.. I have a son who just turned 7 in Jan. He also has ADHD, anxiety disorder and sensory intergration dysfunction. I did not have trouble with potty training...he was 2years 9 months. The only thing I can think of his he anxious more at home? (you said he does better at school).
I did have to take my son to the pediatrician b/c he would occassionally leak some of his BM into his underwear at home or school. The Dr. told me he had no control of this and when he was constipated some would leak out. They gave me medicine to mix in his juice when he became constipated. With my son's potty training we did lots of praise and small treat but not punishing or negative stuff when he did have accidents. The peeing was only 2 days but BM took about two weeks before really trained. Hope this helped