Sarah's daughter, I'll agree with all of the above and add that the depression should be addressed at the same time because it will affect her willingness to fight (or eat). Eating when it hurts is not easy. Pain control is essential. INSIST that they find a combination of pain medications that do not make her "loopy"! Be polite but completely firm with her medical care givers that pain management is your highest priority! Addiction is NOT a common problem and if it happens that can be addressed later.

Let her know that there are people out here whom have been exactly where she is and are now fine. There is light at the end of the tunnel. The period right after radiation ends, is the worst and she should notice improvement soon. It will be slow but it WILL happen. Some here had prolonged pain and difficulty eating. Others (like me) were able to eat fairly soon. For me I used a blender to liquify everything and make it go down easy. Radiation affects both the appitite and the taste of food. This effect goes away fairly quickly. I remember gaining an appitite within weeks of treatment end.

Be on the lookout for Thrush which is a common yeast infection in the mouth and oral spaces. A high percentage of oral cancer patients get this because of the low saliva. It can cause pain, usually a burning sensation. At first her pain might be discounted as normal radiation effects. Sometimes they will ignore the possibility that the pain is really caused by the Thrush.

While I agree with Minnie that nutrition is important, I would not second-guess the tube feeding yet. Get her pain under control and use a blender and she should be able to get good nutrition. Baby food is another good way to get her eating. Another really important thing is hydration. Make sure she is drinking plenty of fluids.

Hang in there for her she needs it and you are doing a great job.