Hello, I am writing this with my phone very late at night so please forgive me for any spelling mistakes.
I'll get straight to the point. A friend of mine suffers from multiple personality disorder, and as someone who isn't very educated on this topic I want to know if what I have been doing (as well as plan to do) is good or bad.
Their current "main" personality is what most people see them as. They are someone you can easily trust, and they have been very kind to me from the start, we get along extremely well. That isn't what their main personality has been from the start, though, at least based on what I was told. Their first, has been locked away but they do tend to pop out occasionally. Let's call this one "W". W is overly "wholesome" and empathetic, they're artsy and like a lot of things the "main" personality doesn't. W is very emotional and considered "weak" by the current main personality because of the fact that they can cry very easily.
While my friend has another personality in them I do not want to speak of it at this moment as I think that they do not matter for this topic specifically.
W is the oldest one out of the 3, but nowadays they're mostly kept shut. I believe it is due to their terrible backstory, having to deal with awful parents and overall surroundings, and feeling as if W just couldn't survive on their own, so they made up the current personality that is 90% of the time out.
I've talked to my friend a few times and they tend to try their best to lock up W and I've consistently told them that they shouldn't and that it's okay if they feel certain things and are emotional but they consistently strongly disagree on that.

I was going to continue being persistent on letting them know letting W out is in no shape or form bad but recently they've opened up and told me that they "don't want to go back in"
I'm conflicted and don't want to hurt the friend I really care about, so I'm stuck.
Any help or advice is really really appreciated, thank you so much for taking the time to read this.