How do I help Maria [spoilers]

[catboy massacre]

When the father attacks her and shes laying on the ground how do I help her to get the true ending? Whenever I interact with her I just get he saying "doctor" and me going "......." but all the tutorials show you helping her or something. Is there something I forgot to collect?

[Mahou☆Shoujo!!]

You need to have read her diary prior to the end of the game in order to help her. If you don't get the key to her room before she wakes up to go chase after your father you can only do this with a new game.

[MrIjela 󰀍]

Correcting the comment - you can read the diary (to be able to help) before you jump into the other world.
You can get the key from laboratory to Maria's room (easily done by being teleported by "Salesman" and then going to the library at Floor 2 on the west side to read the diary.