For the mucous, you can clear it with a Waterpik on the lowest setting, using the tongue scraper attachment with warm water with a bit of magic mouthwash thrown in. I was going to suggest it, but seeing that you only have 3 days left, I wasn’t sure if you wanted to invest in one. If you use it a few times a day, it clears the mouth of mucous. That, I believe, will help with the mucous at the back of the mouth too. With the stomach feeding tube, my husband had to swallow the tube when it was put in, so if you can’t swallow, it won’t work. A nasal tube will work fine if it’s only for a short period of time.