A home suction machine, sponge sticks to get in back of mouth, robotusem, mucinex, constant rinsing, papaya juice, pineapple juice rinsing, rinsing with meat tenderizer Aldolf's was suggested, tea, hot soup like egg drop, steam showers helps cut mucus, sleeping on an incline may help not back up at night. Forget the name of the electrical tooth with water nozzles. If your dad goes back to his treatment center, ask if they can spray the mouth out. My radiation center did it.

I'm taking oxycodone for pain, which is minimal, but pain can interfere with healing from surgery, maybe other type healing too.

Hope this helps