I am so very sorry. You sound like a very dignified and a caring person and it saddens me dearly to see people such as yourself in great pain, without being able provide much benefit to themselves.
I wish there was a way for you to share this burden with the rest of your dad's children and not handle it on your own. It is just not sustainable.
I think it is very noble an admirable of you to care for your dad but it is also very unfair that you have to take on this burden all alone, without a helping hand. You do not deserve this.
Please keep on sharing.We are here for you.