Chris,
I can sympathize with what you are going through as my wife lost her father to Alzheimer's. It was very challenging at times as each day is as good as it is going to be and tomorrow will be a little less good. I have seen enough posts of yours to believe you are a spiritual person. If that is the case, then you need to let God carry some of this for you. As things progress, it may be difficult to know with certainty how much your father can still sort through, but all you can do is be there for him and know that it makes a difference. Do as much as you can manage. But, at the same time you need to take care of you so that you can be there for your mom and your wife as well. If it gets to be too much, give yourself a break. Put it back on God and let him carry it for you once more. My prayers are with you and your family.