I'd say the church was rude. It's quite possible that the son was the only congregation member who *could* play the organ, and the pastor/Reverend/whatever was as disorganized as Flaky, the orchestra director at my school, and even if Son said that he couldn't play because of the previous dinner invitation, there was probably a lot of pressure from the church's end, saying that if he didn't play, he'd "RUUUUIIINNN CHRIIIIIIISSSSTMAAAAASSSSS!!!!!!" for all the nice people in the congregation, donthcaknow? Trust me, as the sort of de facto "chief clarinetist" at Bishop's (I'm the only clarinet major, meaning there are other people who play, but not seriously), I get a lot of that....you know, shanghaiied at the last minute, can't really say no for fear of being viewed as a selfish brat, etc. But, blowing off the previous invitation was rude. "Come over sometime" isn't a firm invitation, but "Come over for dinner this Sunday" is. "This Sunday" is a specific day, and "for dinner" is a rough time estimate. You might have done better to say "Come over for dinner at six," for example, but if she accepted the offer as you made it, then what she did wasn't okay.