Post surgery Vomiting. Timeline!

Hi my mother 60yrs old  got operated for Carcinoma rectum post 5 weeks of radiotherapy and 2 cycles of Chemotherapy. Cancer had started just 5cm from anus and post multiple consultation it was decided that she would have to be with stoma for rest of her life. Surgery finished almost a week back and she was kept on only fluids for first 4 days and started on liquid diet from past 3 days. Issue is whatever she consumes either liquid or semi solid  is getting vomited from past 3 days. Even after 7 days post surgery vomiting is continuing. Pls advise is it common for vomiting to exist that long and how much more time will it take to settle down. She is diabetic as well. And doctor is conveying we can get her discharged. We are worried if we go back to home and again if any complications arise we have to come back to hospital. Pls advise on vomiting timeline