i could be wrong but i think there is a big difference between the way alcohol in listerine and the way a bottle of jack daniels is produced...i was a heavy user of listerine like your brother and i don't see it causing my cancer...i would take the radiation produced from my cell phone over the listerine...no proven cases

7-16-08 age 37@Dx, T3N0M0 SCC 4.778cm tumor, left side of oral tongue, non smoker, casual drinker, I am the 4th in my family to have H&N cancer
8-13-08 left neck dissection and 40% of tongue removed, submandibular salivary gland & 14 nodes clean, no chemo, IMRTx35
11-4-08 Recovering & feeling better