I don't have any suggestions except that it appears Hagrid is taking his frustrations at going to the vet out on poor Bob. Is there some way you could completely separate them for a few days until Bob gets back in the groove - and Hagrid gets over it?

I know others have mentioned that when a kitty comes back from the vet there are often weird reactions from the other kitties in the house, but it all usually passes within a day or so. Hagrid must really be upset.

Other than that, the only thing I can think of is to give Bob some extra attention - and some skritchies from me too.