What silly, silly people. Why don't they train their child to behave instead???

Naomi, we have a leather couch and the cats don't use it as a scratching post. Having said that, there are a few scratches on it, but that's because we have been throwing toys and they've launched themselves off the couch to fetch them (definitely our fault). Most cats prefer material they can get their claws into, like sisal or carpet. Maybe if your boyfriend's sister gets a cat, she can buy a couple of scratching posts and some soft tips first.