I need info about Amnesia story!

[GiggleBlizzard]

Did you even play the game?

His questions make it pretty obvious that he has. It's not something you easily figure out on the first run.

Some questions, like "Who owned the castle" or "What about Alexander´s relatives" proves that he didn´t pay much attention...

He never asked the first question, and Alexandar may have had fabricated relatives according to the wikipedia so who knows.