Yes, your friend will "change" if they come out as a system to you. They seem like they're changing because they're trying to unmask around you and let their alters be themselves and not hide amnesia and other aspects of the disorder as much.
I understand it can be hard to realize your friend isn't exactly how you thought they were, but they're still you're friend. It's likely you've met their other alters, they just didn't say who they were.
Please support you friend, even if it's seemed like they've changed.










