He didn't apologize for his rude behavior earlier, but he wasn't as snappy and I just didn't ask him much, just let him do the talking.
glam, Don't feel bad. It is not about you. It's about him. I think he was reacting to your question out of the insecure place he is in. He felt bad that he missed the flight, and might have been beating himself up about it. So when you asked, he was reminded of his "failure" (missing the flight). Try to let it slide off your back. Great compliments from your ex-SIL.
