Tish,
I am so glad that he is improving!
I do not have the answer as to why take the HG if they are indoors. I do know that in some areas heartworm is a real problem. Where I live we do not have that problem. If your vet thinks he needs to be on some form of HG because of where you live I would ask about weight appropiate and dose before I give him any type. There are different brands. But again I would do alot of asking before I gave it.
BTW Miss Tish----that is too funny!