Feral cat with respiratory problem

One of the ferals I had neutered and he received his shots, has since had a respiratory problem that seems to come and go. At first it seemed to be more of an allergy because he was worse when he was out in the cornfield but he has been sneezing more lately. However, I cannot just pick him up and take him to the vet since he is somewhat feral. Anything I can treat him with at home?

[Aleda M Cheng, D.V.M., C.V.A]

You can place medication in his food bowl if no other cat eats out of his bowl. If they do all eat out of each other's bowls, than try giving him a cat pill pocket to see if he likes the pill pockets.  If he does, you don't have to actually catch him to give him his medication.  You can place a tablet or capsule in the pill pocket and throw it for him.  You will probably have to throw empty pill pockets to the other cats.

You will still have to get him an antibiotic from your vet.