I'm sorry this is happening! But, the advice about the protected shelter outside is good, if it comes down to that. My ex's grandparents had a cat for some 20 years that would not come inside, and, yeah, it's Texas, but, it still gets really cold in the winter. She had a shelter outside that she went in all the time to escape the elements. Hopefully, the agression will lessen, though. Have you talked to Magoo's mom? I know his agression was easily understood, because of his lack of sight, but, maybe she would have some advice for you. Just a thought.