If this person had intentionally done this to my benefit over their children and it was current then sure I'd take the money.

But if it's a 50 years old out of date commitment to a life long gone and there are other genuinely more deserving in terms of being actually children then yeah I'd give it to them.

I'd just see it as a kind of a bank error. If the bank drops 1 million bucks into your account what would you do? I'd give it back. There have been cases reported of this in Australia where people do spend the money that the bank inadvertently puts in their account - I find that hard to understand. Actually I find it easy to understand but disappointing that people are so willing to do the crime just because its offered to them easy. Not suggested that in the case of this will it would be a crime, just suggesting that there's a right thing to do.

And I have done stuff like that. About 30 years ago I got paid about $7,000 for a software job by a client then got paid a second time. I just called em up and gave it back.