Don't justify anything to this person because he doesn't believe it and even says that if Dreamer blocks access to the app through the modified version, he won't have any problem with that. Maybe he doesn't believe the idea that the Dreamerland developers are the ones who removed the Facebook login method, and not Facebook itself.
After I translated his words into English, I think he can still log in via Facebook because he hasn't logged out, just like in my friend's case that I told you about. But he will lose everything when he accidentally logs out or when Dreamer deletes all accounts logged in via Facebook soon. I really don't wish for that, but since he mentioned a specific login method, you should try it at least once. Maybe it will work.
Although I think that even if I downgrade the app to an old version, Facebook login will still be blocked. Can you try it and tell me? Thank you in advance, my friend.