I’m so glad you made the decision to move him into care before things gets worse. Three years of your life dedicated to him seem to me more than enough. It may sound selfish but in my case I don’t think feelings of guilt will be a problem when the time comes, if he lives long enough for the disease to develop to the last stages that is, my worst fear is that we might not have enough money to pay for a place for him to go.
Best wishes to you too!