I agree with not leaving out the grandsons. We have zero from my mil other than cheap costume jewelry and she had a number of beautiful pieces. I found out recently that my SIL does have a good chunk of the jewelry (which she never wears) but the rest is still with FIL. I honestly thought that my fil would gift something of hers to my D when she turned 21, but nope. At this point, I’m sure D will never have any significant jewelry from that grandmother.
I don’t know if she feels badly about that, but I certainly do. Never wanted my niece and nephew to feel that way so it was important to me that my brother take pieces.