Is it rude to announce this way?

My family is sooo unsuspecting that we are expecting (and we love giving a good surprise).

My brother and his family live far away and an in-person announcement isn’t possible in a timely manner; for his 2 kids and for our our first, we have FaceTimed, but that’s the only time we ever FaceTime each other and they will know immediately when I request to set up a call with them.

Their son is turning 2 around the same we want to tell them, so would it be rude to request the FaceTime to “watch him open our presents” that we mail to their house, and then tell them on the same call? Part of me feels like I’m hijacking my nephew’s birthday moment and making it about us, especially because I wanted one of his “gifts” to say something about being an older cousin soon. How it would make you feel? Let me know your thoughts!