Honestly, I would feel sorry for HIM. HE forgot, HE should be embarrassed. There are times my dad would call me on my BROTHER'S birthday, or send money (which I thanked him for, laughed, and kept, because it was his mistake, LOL!) I wouldn't give it another thought, life's too short to get all worked up over other people's actions. You can get as mad or upset as you want, but that's not going to MAKE him remember or even if he does, do anything about it. I had to learn this the hard way, so I apologize for being so blunt, but sweetie, it's really REALLY not worth it. Your son never has to know about this, and if he ever asks, be honest. You've done nothing wrong, so you don't have to worry about him getting upset with you, you know? Let it slide, enjoy your kiddos birthday, and feel sorry for your father for missing out on the greatest joys in life... not only his own child (you!) but his grandbaby. He's the one left out of all the fun, and he can't blame anyone except himself. Sorry you're going through this, I truly hope you find peace with it :)