Filiti's illness has come as another disturbing news for the 66-year-old "Rambo" star, who is grieving the death of his son Sage last month, reported Contactmusic.
Filiti, 48, had been living in Santa Monica with her mother Jackie Stallone.
"After losing my grandson, this has been too much to bear. Toni Ann is not doing well at all. She has lung cancer Stage 4, she has liver cancer, it has spread to her brain.
"I am doing terrible after having my grandson go, then my daughter critical at 48 years old. It isn't easy. I don't know what to do. She has been in UCLA for two weeks. She's on IVs to stay alive. She is on all kinds of IVs to eat," Jackie said.
Jackie, 90, says the family are praying for Filiti to make a recovery but she knows it's unlikely.
"The doctors don't think she will improve. What can you do? They have done everything; she even entered an experiment. I would like to bring her home.
"She is conscious and responsive sometimes, but not really. What we need is a miracle. I still believe there are miracles; it is the only thing that keeps you going. But her condition is critical," she added.