I will keep you and your family in my prayers. It is so painful to see loved ones in so much pain and not be able to help them.
When my step Dad died, my Mom, sister and I stayed with him round the clock for 3 days. He knew we was there, I could tell because when we talked to him , his blood pressure would go up some. Even when they told us he was in a coma, I know he could hear us, just couldn't respond.
I do believe he was waiting for his other 2 grandkids from out of town before he went home to be with our Father... As soon as someone said "There's Johnny", he went pretty quick. Sad thing is, it wasn't the right John. It was my step son. But when he left us, I could just see all the pain and worry go from his body and I know he was at peace with God.
Know that you are not alone, God is with each and every one of you. He will guide you and comfort you.
I will keep all of you in my prayers.