So sorry to hear about your father.
I have had radiation on 2 separate occasions, (2000 & 2008). My saliva dried up after the 2000 radiation treatment. I used salagen but it only made me sweat - a lot. I tried acupuncture in 2003 and had very good success. The doctor hit a spot on the top of my foot and the side of my ankle that opened the faucet on nearly normal saliva. My doctors are still amazed to day at how much saliva I can produce. Best of luck to you and your father.
mark

11/1999 SCC tongue - surgery
1/2000 Met(s) in lymph nodes - modRND
2/2000-4/2000 RT ~6 weeks
end of 2006 SCC tongue - surgery
1/2008 SCC BOT - surgery / PEG installed
2/2008 chemo & RT
4/2008 last time I consumed solid food by mouth