Family Loyalty or Child's Best Interest?

My brother's 28 and I'm 25. He has a five-year-old son with his ex. When my nephew was

about two, my brother just bailed—he moved out, got involved with

someone new, and stopped helping at all, money or otherwise. While he was gone,

I stuck around. I babysat, did school pick-ups, and tried to be a solid adult in

my nephew’s life since my brother was totally absent. Last year, my brother suddenly

popped up and wanted back in. But instead of easing into things, he showed up demanding

his ex’s new address so he could see his kid. The ex had moved for stability and

asked me not to share where she lived. So I told him, “You need to go