Smoothies would work as well as juiced veggies. They can be made as thick or as thin as he needs to swallow them. And they would be very nutritious. All it takes is some fresh fruit, stawberries, bananas, blueberries, whatever he wants, put them in the blender and set on liquify. If they are to thick just add some pure water to thin it out to a consistency he can tolerate. The veggies, any veggies he likes that can be eaten raw, my favorite is carrot, celery, tomato. You can also do green smoothies. Just google, green smoothies and let him pick his favorites.
Hope this helps, I am a newly diagnosed throat cancer patient, have not started chemoradiation yet, trying to get my immune system pumped up before we start.
Wish him luck for me and tell him it is very important he gets food in himself no matter how he does it. At least with smoothies he can taste the food if his taste buds are working.

My father-in-law is in year 5 of his recovery. He had been experiencing everything your friend was but also lost most of his taste buds and ablility to produce saliva. In addition he had reflux which caused him to aspirate, even the ensure, which was caused pneumonia. He has just had two dilation procedures to widen his throat and now is eating fairly normally - meaning that it has to be very moist and think. He still has the feeding tube and does one ensure session a day and consumes water through the tube also since he isn't able to swallow a liquid so thin without aspirating it. If your friend's doctors won't do the procedure, he should find another doctor.