Name of this book?

[Kfamr]

I remember reading a book in English last year -- about four children whos mother is an alcoholic, and their father didn't visit much. The oldest child's name was Catherine, and the younger child (Alisa?) had some sort of imaginary place or something that she always talked about.

I forget what the book was called and I'm really interested in reading it again.

Does anyone know the name of it?

It was a great book.... I just have a horrible memory.