Liver Cancer Stages

My Mother was diagnosed with Primary Liver Cancer just before Christmas. She is not an alcoholic and was otherwise in good health despite surviving breast cancer fifteen years ago. She is now in pain and has been progressively turning yellower by the day. The Doctor's gave her three months to live from mid February. She has chosen quality of life over quantity so has declined any chemotherapy type treatment as it would make her feel worseand is just managing to control the pain.
I am 12 weeks pregnant and she has asked me to find out the sex of the baby as she probably won't be around to see it come into the world.
I was wondering how long it usually takes for a person to succumb once their liver has begun to fail and they go jaundice?