Try pure aloe gel. I am serious. Healing for the innards like it is for the skin.

Dab a bit on his paws. Check a local health food store, and make sure there's not other guck. Some has a bit of chamomile in it.

Herbalife has a good one too, if you know anyone who sells it. They have an aloe drink too - but how to get Brodie(or any cat) to drink that?

hugs
C