Dealing with potential loss of a friend

My friend (also my 12 year old daughter's father) has just been diagnosed with liver cancer and kidney failure. He has diabetes and was diagnosed with melanoma cancer 8 years ago. He had a tumor removed from his lympth noids 3 years ago and was suppose to do treatment, but couldn't handle how sick he got. So, he went to alternative ways to help treat himself. Well, now it is back and he just found out he has a brain tumor. He has 4 children, ages 22 to 6 months. He is 46. I pray for him to get better, and he seems to have some kidney function today, but he is still in the hospital and the doctor's say he might go home soon. Then what? Does he die at home? He has so many problems that I just don't see him getting better. I have issues with our daughter seeing him deteriorate in front of her. I want her to be involved with the process and treatments he is going through. I need strength to be able to support her and give her what 2 parents are suppose to do. Anyone out there have a simular situation? How much should our daughter hear? The possibility of death is right around the corner, unless a miracle happens. I pray for him everyday, yet I feel that it isn't enough. When someone you care about has a terminal illness, your life changes. Mine has.