Hi Liz, I just read your post and feel so badly that you and Rob are going thru this. What I have seen from your posts is that you are strong, caring person, and you will find the strength to deal with this just as you have all the other ups and downs you've faced in the past 5 months.
Go with your gut and your heart on deciding what to do about anything. It's clear that Rob is finding a sense of dignity and peace and that he wants to die in his own home with the person he feels the strongest connection to - you. The fact that he has made his will, is saying goodbye to family, and has strong feelings about where and with whom his death will occur is an indication that he knows what is happening and he's trying to accept it.
Hospice or palliative care is about keeping people comfortable and managing symptoms. Some people like to have conversations about dying, and others - particularly those with issues expressing their emotions - may just want you to be with them. There aren't always words, our feelings are expressed in looks, gestures, or sometimes just that long overdue thank you.
It's clear that you and Rob love each other, and that's what I'd focus on. The rest of it doesn't matter anymore. Tell him you love him, hold his hand, and take your cue from how he is feeling.
You are right that his wishes need to be respected. Tell the family that you will call them if Rob changes his mind and that you will give them updates. Beyond that if he doesn't want visitors people should respect it. Just as when he was in treatment, you are the gatekeeper again. The siblings are not your concern right now. They will either understand or not, but your concern is being there for Rob and yourself. He may feel differently about visitors as time goes on. It may as simple as it's too hard for Rob to have them there or to keep talking about it. At some point, it is what it is and there's nothing to say.
I sincerely hope that his passing is peaceful. Are they sending a visiting nurse out to check on him and help you with pain control etc?
My thoughts will be with you both.
Regards JoAnne