What would you want to hear if the roles were reversed? I find that to be a good place to start typically

tbh i had a similar situation happen previously. what i did was look up DMS-5 definitions and try and survey said person to see what applied and what didnt, get more info on their symptoms and what might be causing them. because there is DID, but also OSDD 1A and 1B, as well as PTSD with Disassociative tendencies. the last one is the most likely one. but disassociation is also a big symptom of depression, anxiety, ptsd, and adhd. its used as a form of escapism to repell traumatic flare ups and unwanted feelings (which is whats more common in lesser traumatized people). normally being able to put a name to said thing can help in finding out how to properly work towards improving it and what not. but thats just what ive tried and had work :)

Hi I have DID

You can give them the MID test :3