Paula, I have been reading here...just couldn't post to ya till now. I just ache for you. I just lost my 31 y/o daughter to this evil disease in Nov. I'm also a Nurse.
The fatigue is quite typical, due to meds, weakness from disease, the body & mind are worn out. They will sleep more, and more.....become weaker. You will know.....it can happen slowly, or quite quickly, so take each day as you can. If there are things you need to talk about do it. If you need to hug, love, hold each other do it whenever you can. I held my girl and would say "I need to hold you" she'd reciprocate. As she died, I would say ' I hold you, honey'....
You are so normal in wanting specifics, and there just arent' any. But, you will know.....as things change. Contact hospice, have them available when the time is right. My heart and prayers go out to you. It just seems so unreal, and yet so very real. Make sure he has plenty of pain meds. There is no reason for him to feel any pain, and when he is ready, or it is the time, keep the emotional pain at the lowest too, with sedation. Christa never wanted to be out of it, yet she didn't want to have to suffer either. She had to see her 2 y/o daughter and know she was leaving her. Sedation can be a good thing. It is up to the person.