I use Life for Teeth from PetzLife Products (
www.Petzlife.com or many other internet stores sell also). It is a mint flavored gel that is supposed to coat the teeth with enzymes that dissolve plaque and tartar. Sissy licks it off my finger. I do brush once a week as well, but the other days I just make sure to give her this. If his teeth are really bad, you can use it twice a day. I, too wouldn't brush his teeth right now. Let his little neck heal, but this product might help, too.