Improving my relationship with my brother (prematurely sent my previous attempt)

My brother and sister-in-law visited near me after a year and a half of self-imposed isolation because of the pandemic which I’m sure was very hard on both of them. They brought their 95-year-old grandma with them so she could visit her other children in the area and the grandchildren. This trip was also also meant to celebrate their son, my nephew, and his new engagement with the fiancé‘s family.  I’m very close to my nieces and nephews. I’m quite a bit younger than my siblings who had their children young, so I’m close in age with my nieces and nephews.

My 35 year old nephew moved to the area near me a few years ago and I’ve been very supportive of his new life. My husband and I have been a big support for him while he settled in the area, looked for new jobs, supporting his relationship with his new fiancé by welcoming her to our family, offered him housing when he lost his job at the start of the pandemic, etc. All done with love and willingly with no strings attached.

For this visit I, along with my whole family were super excited to see my brother and my sister-in-law and spend time with them after all this time. They chose to rent an Airbnb close to my sister-in-law‘s family about an hour away from us and their son. They declined every invitation I offered for getting together for various occasions during their 10 day visit. They requested that we not be included in the engagement gathering that my nephews fiancé‘s family had planned. Even the fiancé was telling me “I don’t understand why you can’t be there”. I said it’s totally ok and it’ll give the 2 families time to get to know each other better (just for context, I hosted the 2 families at my house to meet in person before the kids got too serious, last time my brother and sister in law were visiting, pre-pandemic)

The funny thing is I’d been telling my nephew that he needs to find ways to engage his parents with the wedding process, communicate more, etc.  I reached out to my brother asking if he was upset at me or felt like I had overstepped, and if so apologize. He said he was not upset at me but they’re mostly upset at his son for excluding them from the engagement process which they apparently aggressively vocalized to my nephew.

Nevertheless, I can’t help feeling that they both (brother and sister in law) are annoyed with me. We spent maybe 8 hours during their 10 days visit seeing each other.  Since then, I feel extremely hurt, angry and excluded . Having said that, my intention is to have a close loving relationship with my brother. The models that I keep trying to create don’t lead me to that result.  I need help trying to understand how to use a model to help me to stay an engaged and loving aunt towards my nephew without somehow unwillingly alienating my brother and sister-in-law.  Can you help me with that model?