What is the ruling of Islamic law regarding dealing with a husband who is mentally ill, abusive, and fails to fulfill his family responsibilities?

Firstly: The reward for patiently enduring the affliction of illness. Indeed, a believer is rewarded for every adversity that befalls them.

Secondly: The husband's illness either occurs with awareness, in which case he is held accountable for what he says or does, and the wife must fulfill his rights. Or it occurs without awareness, in which case he is relieved of responsibility and is not held accountable for what he does, unless it pertains to the rights of others, such as slander. In this latter case, no slander occurs from him due to his lack of awareness.

Thirdly: The wife should endure what emanates from the husband if he is unaware, or she can raise her case to the Sharia (definition) court to rule on his eligibility to remain a husband or to annul the marriage. If he is aware, she can either endure it or seek a divorce. If he refuses, she can raise her case to the Sharia court.