Not able to tolerate illness of baby.

Hello Doctor, We were very happy couples 2 years back when we were blessed with a baby boy but unfortunately due to doctors mistake of detection of jaundice on time baby suffered with Kernictrus and is diagnosed with Cerebral Palsy. We have been undergoing all sorts of possible treatments for him. But now since 2 years have lapsed and we didn't see much of improvement in him and due to which my wife is going under lots of stress and pain. Now she has started beating the baby and that too very hard on him just because she says that he has spoiled her life and she wants to take revenge from him whenever he does against what she wants. Normally she behaves with him perfect and does all or even more she can do for her child. Am worried for all such situations she is facing. Please suggest.