Big hugs. My mum had this cancer and I have seen first hand what you are describing. She wasn't fed through a tube though. 

I used to get ideas from a group on here, there's loads of tips, I read through pages perhaps a moderator can point you to that.

A stent helped my mum but also if you haven't already there are tablets that can help to make the mucus less sticky and also anti histamines. My mum had to push for ages before being offered the tablets.

My mum would drink coke which had sat out for a bit and water which were ok.

My aunt also has this cancer, and was tube fed, ill ask if she has any other tips.