My Sister Had Cancer On Her Uterus So She Had

My sister had cancer on her uterus so she had to have her entire uterus removed. So after that she went through chemo she lost a lot of weight she lost all of her hair but all of her hair is grew back since then she has now found out that she has a small tumor on one of her kidneys she also had to have stents put in her back to remove the fluid that was causing some sort of infection on her kidneys. So what I want to know is why won't she gain weight and what are some of the options that she should do because doctors are telling her now that she shouldn't have any more chemo or she shouldn't have any surgery I want to know what is the reason for the doctors to say that is there no hope?