How would you feel if your parents left money to your nieces & nephews but not you or your siblings, and you don't have DC, but have possibly had more financial support as an adult than your siblings (though not as much as their dc will inherit)
YABU - no one is entitled to anything
YANBU - this isn't fair and likely to cause considerable upset
For context it's not my parents, and I have DC who would benefit. I think this is hugely unfair.