You can also try olive oil in his bath, on his hair after you wash it or when every you want. Put the oil on his hair, let it sit while he plays, then comb through while the oil is still on his hair. You will have to most likely use some soap or shampoo to get it out, but just a little. Then comb while still wet so the tangles stay out.
I really like the Spry toothpaste with xylitol and DD has used it since she was about 12mos with little worry about her swallowing it (although I barely put a drop on her brush, just enough to give her a taste!).
Are you in the states or in Canada? Sometimes it's tricky to get American products here in the Great White North