My dad forgets my birthday every single year. Or is out by a month or so either way! He apologies (If I remind him he's missed it!). He only has two children (54 and 57), but never remembers my brother's, either. It is hurtful and upsetting. I don't want a present, just a card, to let me know he has thought about me. If it is the other way round, all hell would break loose! He says at 90, he can't remember things, but he is as sharp as a tack, and I buy him a calendar every year, and put on all the dates that he may want to remember, but it still doesn't help. So I can feel your sadness.