Glad to hear he has apologised. I hope he sticks to your three new rules.
My DH is often quite grumpy and I put it down to not feeling well. I too get accused of hastening his death!
It is not very nice at the time, but I try to shrug it off and put it down to the pain he is in or a worry about his health, or the effect of his medication.
We have just had a short break in a B & B and I kept wondering if it was worth it, as he struggled with a different routine, a less comfortable bed, no easy chair, change of diet, no chance to doze in the afternoon........and more exercise than usual. It is hard to know whether he is making a fuss over nothing, for a couple of days, or whether he was truly miserable all the time. It certainly made me realise just how much we take for granted, at home in our own routines, which help to keep us sane.
I hope things improve as your DH gets used to what has happened.