A.S.
Sorry if this is a repeat of other suggestions but since he has such issues with germs and gagging, hospital supply stores have individually wrapped dental sponge toothbrushes. No germs no brushing no bleeding-altho they probably only have mint. perhaps there is a pediatric version.
Here is website
http://www.vitalitymedical.com/vitalitymedical.storefront...
Best of Luck
A. (mom to anxiety ridden kids too :)!