My sons friends made fun of my step son

My step son is 12 with autism (my husband also has autism). He still wets his bed and recently started wearing goodnites pull ups and he was happy he got to pick the design. He likes pink so he got the girl ones with the butterflies. He sometimes does things that may be considered "socially unacceptable". My 10 year olds friends were over for a sleepover and my step son got excited and pulled his pants down and showed Angel how cool his goodnites are. Not only did the tease him for wetting the bed, but for them being pink. They told him big kids don't wet the bed so he's a baby and boys don't wear pink. He asked why and they called him gay. That upset him and he left the sleepover to cry in his room. I tried to make him feel better but he just kept crying... I'm what to say to help