What can Convenia be used for in cats?

I took my cat to the vet earlier for trouble breathing and lethargy. They suggested I take him to an emergency vet but I couldn’t afford it. They looked him over and gave him an antibiotic because he had a fever. The antibiotic was convenia. Google just said that it’s used for skin infections and a specific type of bacterial UTI. They didn’t take any samples and he doesn’t have anything wrong with his skin. Could this antibiotic actually help him get better?