Was she wrong for skipping his party? 

There are some birthday parties that are criminal to skip. Imagine skipping your eldest niece’s Bat Mitzvah because you’re «too tired to go.» Or blowing off your college besties’ 21st birthday celebration to go to a random frat party? If you are MIA during your boyfriend or girlfriend’s birthday, you are a bad dude! 

Nobody can attend every birthday party they are invited to. You can probably get away with rejecting the invite to your college friend’s boyfriend’s birthday party or your acquaintance’s mom’s birthday party, especially if you have something else to do on those nights. But if you’re the adult family member of a child, it’s kind of borderline whether you should feel pressured to be in attendance at their birthday party. If it’s a family party, it would be wrong for their aunt and uncle to skip for no real reason. But a child’s birthday party at a bowling alley or a play-place isn’t the best place for a grandma to bond with her grandchildren. It’s probably better for her sake that she celebrate her grandkid’s birthday on a separate occasion, away from all the screaming children.