BBM, I'm just wondering if I would have got a different responce from some posters if I hadn't mentioned his SN. I bet I would have! DN knows all about DS2's SN, maybe she is a bit too young to understand it all though, but she still knows that he will try get a reation out of her when she does certain things, and she does do some things to purposefully get him to do it.
I am going to stop going around to my mams when she is there for a while. I've one it before so it's no big problem.