God I hope I don't sound up my arse here [worried]
Tell your DS I was v different at school. I was always in a ruck, sticking up for someone being picked on. I looked odd and my best friend since aged 5 was the campest and overweight chap (not easy being a gay kid in the 80's) Together we faced a ton of shit and would sit on the bus home discussing what neanderthals the boys were and how superficial the girls were (this would be around aged 13)
Deep down we both longed to belong. Friend just wanted to be accepted for who he was and I just wanted to be pretty and be liked.
By the time we hit 6th form we were the cool kids on the block. As we all grew, people changed and what was important 2/3 years ago had been and gone and we had gained respect for being true to ourselves.
I hope this does not sound like ooohhh we were ugly ducklings and we became beautiful swans bollocks. But maybe tell DS that being a little different, owning that difference and claiming it as your strength and what sets you apart from everyone else is empowering. And people cannot resist confidence.
It may take patience. But his sense of right and wrong and justice will be his biggest strength. You should be very proud Hullster, he's going to make a fine young man 