Snape is him, but Avon was rather clearly written first.
Talking of Snape, a friend tells me that Alan Rickman wears black silk pyjamas in the current West End production of Private Lives. (Do I mean
Private Lives? Which ever Coward play has Elyot and Amanda in it.) She
also tells me that he doesn't wear black pyjamas (unless they're under his dressing-gown) in the Harry Potter film, but my hopes are raised. Surely, now J. K. Rowling knows that Alan Rickman is playing him, she will include a Snape-in-black-silk-pyjamas scene in a subsequent book?
I believe I remember him wearing a nightshirt when he was up in the middle of the nigiht before. I don't know that the color or material was specified, however... I *like* the idea of Severus in black silk.