Simon, so sorry to hear about your dad.
One of the low points of my life happened two years ago when my mom called to say that Dad was in the hospital following a stroke. I know what you are going through. My Dad recovered fairly well, we can hope for the same in your case. At least we didn't have to deal with the JW thing.
I agree with the others about the family situation. Do what you think is right. If they choose to act unloving that is their problem, not yours.