My thoughts and prayers are with you and your father every day. Your father being a preacher I'm sure understands that he is not alone in this battle. Let God give you the strength you will need to continue to be his very important caregiver. My wife just went thru a similar situation with her father who had lung cancer. I was so proud of her the way she was there for her father. Her dad could'nt speak but I could see in his eyes how much it meant to him for her to be there. These moments are precious. Your support and love are stronger medicine than any treatment the doctors will be giving him.
GOD BLESS
TIM AXEL