Mom's In Stage 3C Of Endometrial Cancer That's Spread Into

Mom's in stage 3C of endometrial cancer that's spread into her bowls, stomach & lymph nodes. She's in her third year cycle of chemo, has been very weak and--recently--has not been able to keep down any food or water. She's nauseous all the time . Should mention she has a colostomy. Today she threw up dark bile 7 times. What would cause this?