Kellie:

I experienced the heavy mucous after radiation as well. It does eventurally go away. The point of the medication is to provide saliva so it is easier to talk, eat and provide dental health. It really is hard to talk with dry mouth and can be challenging! Your sister needs to really take care of her teeth now. I use products from Biotene. She will need special toothpast, mouthwash etc. I suggest she try it and see if it works. Wish her well.
Jeff