AITA for not telling my parents who one of the guests at my wedding will be?

My (26F) sister died two years ago at the age of 29.<br><br>She had a boy when she was too young and the father wasn't in the picture, our parents took over the parenting of the child (my nephew) and raised him as their own. This was a condition for my sister to live with them and for them to pay for her college. My sister was very close with the whole family but I could see that she wasn't treated the same. There was nothing major but I felt like my parents treated her as a daughter who made a huge mistake as opposed to me who was an angel. I didn't like this because the whole family was built on the idea that home is where you can be yourself and your family will always be ready to help and support you.<br><br>My fiancé "John" and I are getting married this summer. John lost his brother a year ago too and I know that he is still dealing with it. John and I wanted to honor our losses by inviting a friend who sees eye to eye with us, he's someone who also lost his siblings and we want him there. I didn't tell my parents about the invitation because they don't know that he's coming and I know they will not be okay with him coming. <br><br>The thing is that my parents forced my sister to give up the boy when he turned 10 (they had a minor argument and they took him to live with her ex and his new wife, my parents didn't allow her to see him after that, they said it was for the better and that they were done babysitting) to the father and his new wife. She cried and begged them to let her see him but they didn't allow it. It caused a rift between them and us but my parents ended up cutting her off because she kept asking to see her son. After she died my parents disowned the boy completely and didn't allow any of us to go to the funeral. They made it seem like she never existed and they didn't want her son anywhere near them or their "real family".<br><br>The friend I invited is actually my nephews friend, we met him at the funeral and we became friends afterward. He was the only one who checked up on me and stayed with me and John through our toughest times. The reason why my parents wouldn't be okay with him coming is that he's the younger brother to my nephews new father.<br><br>I know that they might see this as disrespectful but I think that my nephews feelings should also be considered. I don't think that my parents would care but I do and so does John. I still haven't told them about our friend coming and I plan on not telling them until the day of the wedding because I don't want them to think that I'm disgusting or anything like that. I just want to honor my sister and make sure that the people who helped John and I get through tough times are there to celebrate our new beginnings.<br><br>&#x200B;<br><br>Edit: if you have any questions, I'll be happy to answer. Please don't attack people who agree or disagree with me in the comments, it's not necessary. I just need to hear your opinions. Thank you all.