AITA for ghosting my friend of 20+ years no

I (38F) have been best friends with Luz (38F) since the 5th grade. In 2011, everything changed. Luz went into sudden kidney failure. For years, our entire circle revolved around her. When she needed a donor, her brother and I were both matches. However, through this process I found out I was pregnant. Her brother had to back out because doctor's said donating meant quitting his construction career.
After I had my baby Luz asked for my kidney. I told her my life was different now; I had a baby, and if my son ever needed a kidney, mine belonged to him. Luz claimed she understood, but the next day, her family bombarded me with calls calling me selfish. Luz ended up calling me selfish too. I believe this is where the resentment started.
For the next decade, Luz became the ultimate "main character," using her illness as immunity for awful behavior. She once ditched me and our kids at Disneyland for hours, throwing a fit when I got upset. On a week-long road trip I planned, she texted our families claiming I was "holding her hostage" because she didn't realize how long the trip would be- she had the itinerary before she agreed to join. Every time I confronted her, she'd cry about her dialysis pain, and I’d back down.
Fast forward. Luz finally got a successful transplant. Her health returned, but her entitlement stayed.
Last year, my brother was brutally and horrifically murdered. As the eldest daughter, I took charge of all funeral arrangements so my grieving parents wouldn't have to. The details of his death were incredibly gruesome and traumatic, so I kept them private. I called Luz, crying, telling her I needed my friend. She promised to be there for me.
At the services, I was overwhelmed. I hugged Luz and thanked her for coming. I later found out that while I was busy, Luz was cornering my aunts, cousins, and even my grieving mother, hounding them for the graphic details of how my brother died.
When I called her out a few days later, she wasn’t apologetic. She said she was "confused" why I was hiding things from her, acting like she was entitled to the gossip. I finally snapped and told her the horrific truth:“He was shot, dismembered, and burned. I hope knowing that was worth our friendship.”
Luz scoffed and called me "dramatic."
That was the ultimate ick. A decade of built-up resentment crystallized. I hung up, blocked her on everything, and told my family she was dead to me.
It’s been over a year. Now, her family is texting me, calling me an asshole for "throwing away a 20-year friendship over one conversation." Even my mom and sisters, who have a soft spot for her, are nudging me to reach out. But it wasn't one conversation—it was the final straw after years of manipulation. Am I the asshole?