Has the doctor suggested hospice? Have you asked him if hospice is appropriate? ask his physician what you can expect. That's probably your best source of information.
I am very sorry that you are both going thru this.
Start this evening making a list of your questions. Next time they come, ask them all. Don't hesitate to call them. If he's itching, that is a threshold of pain. The nurse can make him comfortable with instructions over the phone.
When my dad began to go into liver failure he developed hepatic encephalopathy which is swelling of the brain related to the liver failure. It was like dementia had settled over him only it wasn't typical dementia but dementia due to the liver failure. If I recall correctly it was several weeks between the time he developed the encephalopathy and when he died. Maybe a month, perhaps a little longer. He was on hospice and they kept him comfortable and I was very grateful for that. He didn't suffer and he never realized that his mind was going.
I am very sorry that you are both going thru this.
Angel keeper. Yes, you are. **hugs**