I've been wanting this for a long time, and I think its now safe to say, Lulu has excepted Will as a member of the family. It's not that she was ever mean or skitish around him, it was more that she was always super jealous. She has now become a lot more tolerant of Will as he has gotten older. I'd say that this is due to two reasons. The first being that she realizes that he's not going away, and the second that Will has gotten a lot sweeter and softer around his big sis. Gone are the days of pulling her hair, ears, and tail (though an occasion poke to the eye still happens, it did tonight), and now are the times of gentle rubbing of her back and belly and whispering in her ear that she's a "Goud gurl."
With Will getting older, it also seems now that he feels a responsibility for taking care of her. He jumps at an opportunity to fill her dog bowl and feed her a treat while making her shake or stay. He hates when she is left inside when we are out and makes it a point that we let her out to join in the fun. He even likes to let her in on a little space on the bed in the mornings. He knows that he runs the roost and that its okay once in a while to let her get some attention, because he knows she won't steal his thunder. Hopefully he'll have this type of compassion for his parents when they need taking care of!
This never would have happened before.
Copy cat, or copy dog in this case.