Hi Tami,
My husband also lost his voice, at least it was down to a whisper, for about 2 weeks. It came back gradually as Nelie described above.
I think it would be a great idea for your mom to get a consultation from Anderson M.D. to see what she should do next. After what she has been through, getting some advice from the #2 CCC in the country should make you all feel better about the next course of action.
Since my husband has been going through hyperbaric oxygen therapy (HBOT) recently, I've been learning quite a bit about the effects of radiation. We were told that radiation reduces vascular flow in the radiated area to about 20% of normal and the tissue may not heal as normal. If this is the case, they may use HBOT before any surgery is performed because it will restore vascular flow to 80% of pre-radiation levels.
Regarding the nausea and depression, you might check out this article on acupuncture from the OCF Oral Cancer News -
http://www.oralcancerfoundation.org/news/story.asp?newsId=783 My husband has used it successfully for a number of cancer treatment related issues including nausea, pain, anxiety/depression. It is supposed to work well for xerostomia too, so I think his acupuncturist is going to focus on that next.
Connie