Anonymous wrote:One advice I always hear is try to connect him to her accomplishments so that he feels proud of her and himself. Ex: good job for peeing on potty just like your big brother. Jimmy thank you for being such a good example to your sister.
I agree with this.
I also think that kids tend to identify with parents when they are annoyed with siblings much more than get jealous of siblings getting too much praise. So, it may be that the potty training was a particularly stressful event for you, and he picked up on that, and is annoyed with his sister for making life difficult for mom. Does that make sense? So, I actually keep up talking about how wonderful his little sister is and how lucky we are to have her in the family.