K.V.
Hi L., It sounds like the brother in law doesn't think that the adopted daughter is a "real" niece. If she is to you and your husband, then they both get money or neither one does! It's hard to get upset at the one for getting so much and "making a big deal about it" because that's normal to be excited about a gift. It also sounds like you are having issues with the step daughter and not just the brother in law. That can be just as toxic to the kids. My heart is breaking for both of these girls. I would really recommend family counciling, it did wonders for us. I have a son and am married and we have 2 together, and in my first marriage i was a step parent. This is extremely difficult. Good luck.