I just wanted to add this to my previous rant:
Later that day, my MIL and FIL came over to drop off a thank-you card from DH's 5-year-old neice for a birthday present we had just given her. I was stunned!
I told them the whole story about my cousin, and then I said, "I should make a copy of this thank you card and send it to my uncle and cousin with a note saying: "See? Even a 5-year-old has better etiquette and manner than you!" "
