People with DID are just that, people with DID. I would suggest not putting a label on this person as our suspicions are just that, suspicions. Once in a while I find myself thinking, "well that person sounds like they have ____" but realistically, I am not qualified to make a diagnosis, no matter how much research I may do.

If you are interested in being this person's friend, then act normally. No one wants to be treated differently because they might be different.

HTH