D.C.
Wait... I re-read your post: this is either YOUR or YOUR HUSBAND'S brother, sister and grandmother. I thought it was your parent's siblings and grandmother! All of the advice stays the same. I did not go back and change Aunt/Uncle to other names. However, does that mean that YOUR/YOUR HUSBAND'S GRANDMOTHER passed away about a year ago? Brother and Sister may really miss her even though you don't. If you have told them this then, YEAH, THEY ARE HURT! I would be devastated if one of my sisters told me "no one really misses Grandma" even if it was true, because ***I*** loved her. Did you go to the funeral, or skip it because she wasn't important to YOU? Funerals are NOT for respecting the dead: they don't care anymore. Funerals are for supporting those who miss them. I attend some funerals of people I don't know well just to support my friends who did. All of this will play into how long it takes to become "normal" again.
This is my post before adding the above paragragh:
I do feel some of your pain. When my grandmother passed there were a lot of hurtful things said between my aunts & uncles and my mom before and after. My aunts & uncles & mom went through the same type of family break-up. It tore all of us cousins apart and we were already adults at the time. We had all grown up together, staying at each others homes for the summer, you get the picture. So it really hurt us when we would hear: If so-and-so is going them I'm not. We ended up inviting who our parents would talk to. It took several years, but our parents started calling each other again and now we're one big family again. It's not the same as it was, but we are HAPPY again. So, it can happen.
This is a good teaching moment for your kids. ALL relationships (friends, siblings, parent/child, cousins, aunts/uncles-to-nieces/nephews, AND marriages) take work. "Sorry" does not wash everything away instantly. When one of my kids has said sorry to the other, I don't make the hurt one automatically accept it. I let them work that part out. I remind them both that "sorry" expresses regret for the word or action and acceptance of the apology exresses forgiveness. However, since we are mere humans the pains still stays for a little while, so if the hurt one accepts the apology they do NOT have to play right away with the one who hurt them. They can NOT hurt back, but don't have to pretend to not still hurt. Explain that once words are out, it's done and you can't take away the hurt you caused. Saying sorry is the way to START the healing process. Saying sorry does not make everything okay immediately. Saying sorry tells the other person that you regret hurting them, but it does not take away the hurt like a magic wand. And the longer between the hurtful actions and the apology, the longer the memory of the actions has to bury deeper into the heart and turn into anger.
Your kids know about arguing between themselves and their friends, and how things said can hurt A LOT. Do your kids know, now that their older, that there was a disagreement or something where you adults said hurtful things? (not the whys and wherefores, they don't need that) If not, then have they been told "kind" things like 'Aunt & Uncle are too busy to see us right now' and so on? If that is what they think happened then they will not understand the tension between you and the aunt & uncle. You don't need to tell them WHY there was an argument, but you need to tell them that the reason the tension is there is because y'all had an argument and you ALL said some mean things (don't tell who said what). Admit that you said hurtful things, too, so that they get the lesson that ANYONE can make a mistake. When we have such big breakups, there is no such thing as "back to normal". You have to create a "new normal".
It took two years for the apology to happen. That's a long time for all of you to be hurting. Your Aunt & Uncle may have thought that "let's put the kids first" meant that you only wanted to reconcile because THE KIDS wanted to see them, not you. That may be why they're avoiding you. Or they may feel uncomfortable and not know how to start a conversation with you. The next time you see them, after they hug the kids, walk up and say something like "I really miss having you in my life. May I have a hug, too?"
My prayers for your whole family!