My SLP told me to gargle with water every time I felt the urge to cough the mucus up. This greatly slows the production of the mucus. Coughing up the mucus increases production. Sometimes you just need to cough it out and that ok it your airway but I found it to work great for me. Also, I boil water, turn off heat and stand over to breathe the moist heat and this breaks up the mucus.
I bought an adjustable bed frame on amazon for about $400. Ive had it for several years its awesome head/neck treatment.
Ur friend should get herself in with a gastroenterologist and an SLP (be an established patient) bcuz when you need them you dont want to wait months to get in. I would not have made it without my SLP (no joke). I have convinced her to do over the phone consults (yes shes that awesome) for people that live out of the Massachusetts area. (I drive from Connecticut). Her name is Erica Bell 413-300-2193.