I had this situation with my MIL. She wouldn't acknowledge my DD's bday. My DH finally said "we are a family, all of us,so if you won't at least acknowledge sassy's DD's bday then don't do it for any of us!" And now she does! And she's actually sincere about it! So I would ask DH to discuss with his dad.

If the issue is that your DS gets nothing.. then when he slips your DD some cash and it hurts your son's feelings, then yes, I would mention (or have DH mention if you aren't comfortable bringing it up) that DS's birthday passed with no acknowledgment... and I don't know if it should bother your DH, but he should say something if there are hurt feelings (yours or your sons). It would also depend on the circumstances around SS's birthday and your kids' birthdays. Is there a party? or is he invited over for cake & ice cream or any kind of celebration or does he just come by to drop off a gift for SS?

When my kids have a birthday, we have a family dinner to celebrate... not an actual 'party' but I cook dinner & we have cake (sing happy birthday) and I invite my in laws. They usually bring a card with a little cash for whoever is having a birthday. When SD has a birthday, they get her lots of gifts. They only have two biological grandchildren and their step-grandchildren (mine) were teens/grown when we met. If they were young, I would say something if there was a great disparity. I expect them to spend more/buy more for their grandchildren but at the same time, my dad gives to SD equally as any of his grandchildren.

I've said it before, life isn't fair and the best way to get people to do what you want them to do, is ask. If you want him to stop giving your DD cash... say so. "I appreciate the thought but it's not necessary." Let him know if you think it's unfair or if your son feels left out or whatever your reason is. It doesn't sound like he's an unreasonable person, but maybe he wants to do the right thing and he can't know there's a problem unless you tell him. Some people, no matter what you say, are going to do what they want without concern for anyone's feelings... you can't talk to someone like that.

In my opinion, it would be easier to invite him over to sing happy birthday to your son and have cake... so he doesn't forget it's his birthday, because it sounds like he would acknowledge it if he knew. (or DH could remind him)

How hurtful for your daughter to be the only one ignored on her birthday!

If you & your hubs can agree on what you want to happen (all kids get cash? some get cash, some presents? FIL is to go fly a kite?), then he can convey it to his dad.

Remember that you & he are the parents, you get to determine the "gift rules", & make the rules stick.

I once knew a couple who gave away an enormous amount of "excess" every birthday;
somebody's mom, forget if his or hers, went waay nutso on birthdays, ignoring the couple's repeated requests to not spend $500 or so every time.

Mom couldn't/wouldn't/didn/t change her ways, so they just explained to the kids that, in their family, accepting too many presents was selfish when so many children didn't have any presents at all, & the extra presents went to charity.

I'm not certain that FIL just cant remember. I like Imas idea of inviting him to family dinner and giving him a heads up. If he doesnt live close, maybe try tactful reminders ahead of time.

my brother doesn't remember DD's birthday, in fact he never remembers anyone's birthday (unless there is a celebration). My mother calls him to remind whose birthday is DS's birthday is coming up.

Wow just the opposite here. My parents always have acknowledged my skids on their b-days and holidays. It was always their bio moms parents that never sent gifts, cards, or called ever.

WT, It appears that FIl recognizes one stepkid (whose bday comes near biograndchild), so I put tis to memory issue.