There's a theme. You'll figure it out

Grandkids, man. They suck. Okay, some of them suck, and those that do, suck a whole lot.
Something that makes some grandkids suck a whole lot: the death of their grandparent/s.
I'm telling you, it brings out the worst in those grandkids, especially when there's some money involved.
Here's something interesting for these kids to know: any money that you get from a deceased grandparent is not something you are entitled to, it is a gift. It's not something you deserve as a grandchild, it is something bestowed upon you by your parents and/or executor. It is not something that you argue, contest or get bitchy about, it's something that you accept graciously, and use in a way that you think the grandparents would approve and enjoy. Don't be an asshole about it.
Unfortunately, more times than not, the valuable information written above is too late to keep these grandkids from being assholes. These kids think they deserve more; think they know better than the person in charge; and think they are doing better for their grandparents. I can't stress enough how you do nothing but shoot yourselves in the foot, face and asshole when you take on the executor of your grandparents' estate, and demand more than your share.
I've got two cousins of my own who can attest to the fact that fighting over a grandparent's estate doesn't get you very far. In fact, it gets you less money than you were getting in the first place, and it also cuts you off from your family. Sure, you may think that your wife and her family (or your own independence) are all you need in your life, but the day will come when you realize how much you've screwed up, and you'll be out in the cold. Honestly, when you make this move against your family (not to sound too mafia about it, but really, it kind of is), you deserve to be excommunicated. There's no excuse for this measure of greed. And you're an asshole for displaying it, and even more so for acting on it.

p.s. I chose this picture because it represents this particular breed of grandchild: they are an elephant's asshole, walking away from their family, into a lonely future, holding a check that's smaller than what they were going to get, and more than they should get. Gifts are amazing things. Grandkids who don't appreciate them are ... wait for it ... assholes.