"How long can this go on?" Nobody can blame you if the question crosses your mind, when you're in the really tough haul of severe-stage dementia care, as physical declines match mental ones.
What can help?
Don't feel guilty about wondering. It's a natural response to a sad and stressful experience. It's also human nature -- and smart -- to look ahead and give some thought to the possible "what ifs" in your future.
Accept that all feelings are legitimate feelings. If you're having an emotion, then it's real and acceptable because it's what's happening to you. How you act on emotions is different, but simply having them -- any of them -- is A-OK.
Cut yourself some slack. Many days are unbelievably hard in severe-stage care. Bringing in extra hands or finding ways to get out of the house or nursing-care facility are critical steps -- and they represent a need that will increase, not decrease.
Look for the ways your loved one's essential personality persists -- a smile when listening to music, say. Embrace those wisps of the essential person while letting go of your old expectations for the former spouse or father or grandmother.