Did Kate have any wish/desire or just be like a zombie

My question is regarding Kate–

When Kate saw that book inside the pipe, she thought something was up with Jimmy so she ran to the shed and saw Ray. Then Ray acted and all and it seemed he was able to convince Kate that Jimmy really is gone.

How could not she sense that something was not right. She knew Jimmy and his personality or the way he thinks and she should have known that Jimmy would never abandon his Brothers( sons) just like that if not Kate joins him.
She knew that Jimmy has decided not to join school with Tracy then how could he just runaway.
Also she knows Ray very well but still she believed Ray's reasoning….Such a Saint man Ray is.
Ray says he left because he told Jimmy all the secrets which already he knew and they both Ray and Kate know this that he had obviously figured it out.
So it's a bullshit reason by Ray.
.

She did not cross question or try to read mind of Ray.
She did not show any suspicion, no signs of grief or depression.
Is she that much timid?
But in the bar there was one evidence where the kid said to Ray that Mum's mad at you and won't leave until Jimmy returns.

it doesn't matter that they do not end up together but I really wanted that love to be true and not like taking as granted as the situation was a mess.