Thank you for your letter. Your family wants to keep your grandfather comfortable at home-----and are willing to sacrifice their own comfort. As your grandfather nears the end of his
life, he wants to hold onto himself by striking out at others. He refuses to bathe and sits in his own waste. It is not personal;he is tense and frightened.
It might be possible to approach your grandfather with a type of horse whispering. Two or three family members might approach him, sit around him and speak softly repeating certain phrases over and over. "We love you, you have had a good life and now you are very old. We want you to stay home. The smell is horrible." See if you can soothe him with sound.
When he goes into the bathroom, forget the shower for now, just work on wiping him and washing his bottom with wipes and a warm wash cloth. Talk to him and tell him what you are doing. You just want to clean him and change him, but he does not have to shower. When you take off his soiled underwear, get some disposable pull ups for men. Pull them up,and put on clean trousers. Tell him how good he looks.
Make sure the soiled underwear is properly cleaned. Also,try to find a man to be his personal care attendant. The man should be able to remain calm and gentle if your grandfather tries to hit him or be abusive.
Your family needs some professional intervention. Although they are extremely patient and kind, when he hits his loved ones and sits in his own poop, that is not acceptable. He may need medication to calm him down. If he can't see a doctor, a consultation with a Geriatric Care Manager or a visiting nurse would help. They will come to your house and advise your family about how to manage him at home.