My mom was really into fairness between my brother and myself. She had a condo that she wanted to leave to my brother, and I'd get the equivalent in stocks/bonds, and we were to split up the rest.
After she died, the attorney informed me that he didn't write it up that way, my brother got the condo and then we split up evenly whatever else was left. So my brother was getting a condo in addition to half her estate.
I told my brother and he said, "no, sis, you and I both know that's not how mom would have wanted it, so we'll just divide it like we know it's supposed to be."
And we did. I had no legal leg to stand on, and honestly, I would have just dropped it if he had wanted to take it, but he didn't. I think he didn't even mention the mistake to his wife, because she can get grabby.
I know that he just did the morally right thing, so on some level I shouldn't be so grateful, but I am.