Like Barb says, several of ours groom each other. Especially when one is "under the weather". Just last night, Gabby (our sick boy) was sitting in the doorway between the kitchen and the bedroom. Grumbles, who is still a bit of a loner, was walking past. He stopped, sniffed Gab and licked him a few times on the side of the face then continued on his way.

When Michael first arrived we were a bit concerned about the older cats. Big ol' T-boy immediately took charge of his "little bro" and groomed him to a fare-the-well. They still do this once in awhile.