audrey is definitely right that taking sides will cause internal and external conflict for the young man if he is in fact, DID. Does he know that he is a multiple, i mean, has he been diagnosed with such? because if he hasn't, then telling him he has DID could open a pandora's box. Proceed with caution. there is little you can do for him and i can't really help you know more of what to do until i have more info. Just proceed carefully and treat any and all possible alters with the respect every human deserves. PM me if you feel like talking more or if you need more help and maybe with more info i can help more. Good luck!

-shadow