So sorry for your situation. Keep reminding yourself that it is the illness that is making him so angry and scared which is probably directed at you for no sane reason except that you are there. How I deal with this is anytime the kids or his family asks what they can do, I ask them to come and stay with him for 2 days so I can go to my sister's to sleep and take long walks--my Sis lives 80 miles away--close enough to be back if an emergency and far enough away that I can let go of the situation.
Take care of yourself or you won't be able to care for him. Bookmum, Sue