Kingfish,
I have some idea of what you are going through. My father passed away Feb 6, 2004 after a rather rapid decline with symptoms similar to Parkinsons/Alzheimers/Lewy Bodies caused by a series of mid brain strokes (TIA). Doctors wanted to place him in a nursing home with a feeding tube. We made the decision to take him home and allow him to pass with what dignity he had left. He went, after he had had a chance to see as many close family members (spouse, children, grandchildren) as was possible, in his own home looking out the window at the ranch he built and loved so much. Ironically he waited until all of us were gone on errands and only my wife, who he was very close to, was by his side. It was as if he wished to spare his children from the end. He was my friend, my hunting partner, my teacher and my business partner. The void left by his passing is unfillable but the mark he made on the world through his life and children is undeniable.
My father's decline happened mostly over the course of a year so I can only imagine the struggles your family has endured for the last 17. You will miss your father but take comfort in knowing his struggles are over and you have done the best you could for him. You are his legacy. Live up to it well and be proud. You and your family are in my thoughts and prayers.