I need help coping with this stupid cancer.

My 35 year old daughter has stage 1V breast cancer with mets to the bones for the last 5 years. She feels bad everyday. She is unable to enjoy her only son who is 7 years old. My daughter is having Chemo on friday, so that means she's not going to even enjoy Christmas this year. Chemo every 3 weeks instead of every week. There is no end to this. I am trying to stay strong for her but my hearts breaks everyday. Please pray for us.