Just yesterday I was saying to someone that my cats, Merl and Charlotte, like each other okay, but that they don't cuddle or sleep next to each other, let alone groom one another. And then last night, Max said, "Mom, look at this!" There was Merl and Charlotte, side-by-side, fur touching fur. And, you guessed it, while we were smiling at the pair and commenting on their cuteness, Charlotte started grooming Merl. She bathed his face and ear.
Maybe I can save my sofa by telling someone that I don't ever expect Charlotte to stop using it as a scratching post. It's worth a try!