Baytril I believe will work on a staph infection, which is what bumblefoot is. You'll still need to clean all the crud out, but if you're worried it's gone systemic you can give him Baytril, which you can buy here:
https://allbirdproducts.com/collections/medications/products/baytril-10
https://allbirdproducts.com/collections/medications/products/baytril-10