Re: I could use some advice...
My mother was one of 5 children. She was the one that remembered all the brothers and sisters' birthdays but never really the children. I never got calls from my uncles and aunts on my birthday. Birthday parties were for school friends and occasionally my cousins who are my closest peers would be invite (Most were 5 years - 15 years older). It never felt strange.
Now that I have kids, my in-laws (husband's family) have one who sends cards for every single birthday and holiday (including Halloween!) One that sends gifts once a year when she gets around to it (she works 80 hour weeks as a cpa) - so it is either for a birthday, or Christmas, or this year it was my kids' Halloween costumes. The brother never does anything for us, including calling to find out if we're okay (if we don't call him, he doesn't call).
On my side it is only me and my brother. Each of us has only one (biological) child. Let me tell you, it won't go well if either of us forgets any of the family members' birthdays. Each time the man, the woman and the child has a birthday a call has to happen or a Facebook message. They are not that great at remembering my step children's birthdays but they have never ever met or spoken to them. They are vague concepts to my brother and sil. They have met my biological daughter (money is tight so only she and I flew to South Africa once before she turned 2 and we only paid for one plane ticket). My step children do not feel like they are left out because they also only think of their step family as vague concepts. They have no emotion invested in them.
So, I'd say you need to figure out what it really means. As demonstrated in my example above it is not merely whether it is your sister and her nieces and nephews. It is the closeness of the bond and whether the kids feel hurt.
By what you said, it does feel like the kids are hurt and then I'd address it.
For my daughter!
Last edited by vatblack; 11-25-2012 at 11:01 AM.