AITA for not getting my nephew a birthday gift?

My nephew turned 13 today and after his birthday party when I was saying goodnight, he asked me if I got him anything for his birthday, which got me thinking about why I didn’t and if I’m possibly in the wrong here.

For context, we live together and while I love sharing a home with my sister and brother in law, we have all discussed how my nephew’s temperament, blatant disrespect and behavior is the only thing that causes tension and isn’t harmonious. I love him to death, I pick him up from school every day, I play with him and engage as a loving aunt and friend, but we constantly run into issues such as him bullying my children, showing no appreciation or respect whatsoever, and being genuinely hateful more often than not.

For my own birthday in December which was literally a celebration from midnight-midnight in my family’s true fashion, he didn’t tell me happy birthday or acknowledge me in any sweet way once- and became angry and even more hostile once his parents brought this up. He never said happy birthday to me, his only aunt and that definitely hurt and spoke volumes to me about how little he seems to care about me. Yes, he’s a child and teenagers can be distant and rude at times but every child/teenager in my life freely shows me love and care so I don’t understand or tolerate how dead set he is on hurting me and negatively affecting me and my children on a daily basis.

All he asked for on his birthday was money, and he got over $400 today alone- I’m happy for him, but I truly did not want to contribute to his birthday aside from the genuine moments of celebration, decorating for his surprise party and the love I gave him. I’m sure it was hurtful and alarming that I didn’t give him anything but my time, affection and service setting up his party, but that’s more than I even felt I could give all things considered.

My impression, knowing him to the capacity that I do raising him with my own children these last 13 years, is that while he is hilarious, charismatic and charming, his overwhelming aura has become very entitled, selfish, careless, hostile and arrogant. It’s a hard thing to say about a child, but it’s real and his parents share the same feelings- we talk about it almost daily.

I just want to know- am I the asshole here, or is gift giving (money handouts in this case) as a very present live-in aunt the obvious choice?