I can offer you a small glimmer of hope:. My husband has lived almost four years since his initial diagnosis. I have experienced all you have described and worse.
Fortunately, at some point, he has returned to some semblance of his old self. He is not all the way back, and he is still quite thin and weak, but his nastiness has significantly decreased. For some reason, he could always be civil to other people but would totally unleash on me. I expect that your husband, too, will improve significantly if he is blessed with the chance to live longer.