AITA for saying my brother's stepdaughter is not my responsibility?

My brother died about 2 weeks ago. He was in an accident. I didn't know how to tell my family at first. He had been staying with his wife and daughter since he lost his apartment and had no other options. His wife asked me to tell our family after I told my own wife and she refused to talk to me for a day. <br><br>I have a stepdaughter myself, and my wife is stepmum to my brother's daughter. She asked me to be gentle but not to lie to ease my brother's wife. <br><br>My brother has 2 sons and 1 daughter. The daughter died at 15. I told my family she was 15 and had died of an overdose and my brother was devastated. My brother's wife is divorced and single parent to her 2 children. Her 2 boys are now living with her.<br><br>I am a grandfather, so it's been tough to tell my family this news and handle the emotional fallout. My own wife has been handling it more than I have to be honest. I feel like my emotions are too complicated, but I want to be there for my wife. <br><br>My nephew's wife called me yesterday to ask if I would take the kids for the day so she could visit her mom. The daughter is still alive, but her cancer has come back. <br><br>I said no. I didn't want the kids for the day, and I told her no. My brother's wife is grieving her daughter. She is also a widow. She was closer to our late sister than anyone else. Her daughter was closer to our late sister than anyone else. My brother was close to her daughter, but I'm sure his death is hard for all of them. I told my nephew's wife I thought this would be a great opportunity for my daughter to step up to the plate and I gave her the details. <br><br>She called me an asshole and hung up on me. My own kids are appalled and say I'm an asshole.