Also, she treats all of the other female grandchildren completely differently than she treats the lone male grandchild. Is there anything I can or should do?
Answer: I don't suppose the grandson is significantly older than the granddaughters? If so, then the girls might grow into Grandmom's affection.
Otherwise you need to protect both kids: Deny her access to them, except in carefully measured and monitored doses, and say why.
Her request that you fund cruises is so easy to deny that it hardly warrants advance planning. "No, Betty, you can't take just one of your grandkids on a cruise, not even at your expense." I'd add, ". . . unless you plan to offer each of them the same opportunity," but I couldn't imagine sending one of my own kids anywhere alone with a grandparent who wasn't excited to be with him. That just sounds awful.
If Grandmom's bias is against girls, that makes it easier to explain to your kids later, believe it or not - because it's clearly about her self-loathing and not about a particular kid. Still, that doesn't change that access to your kids has to be predicated on her behaving herself, as much as you can realistically expect.
Q: I live 500 miles away from my only brother, his wife, and their new son. I really want to be a part of his life growing up, but we're never going to live near each other. Do you know of good ways to be involved with a kid far away? Regular Skype time when the kid is older comes to mind, but my brother and I have never been chatty.
A: Your chattiness with your brother likely will be independent of your relationship with his son. A parent has a lot to gain selfishly from having an uncle willing to video-chat with his kid for 10 minutes here and there, and besides facilitating, it doesn't really involve a conversation between you and your brother.
Other ways to stay involved - since it's going to be a while before you can really hold two-way conversations - are to send things that the son can associate with you. Books, for example, or a special stuffed animal, or little photo albums of you and other family members, and of your visits. Make sure the pictures are replaceable copies, since they'll get destroyed in the blender of toddlerhood, but keep 'em coming. Memories are born of repetition, and if you remain even tangentially in this child's life through the early years, you'll have the foundation upon which to build when it's his choice, not your brother's, to stay in touch.
E-mail Carolyn Hax at tellme@washpost.com, or chat with her online at noon Fridays at www.washingtonpost.com.