This person is baffled by her SIL's decision to attend family events— and then refuse to say a word to anyone. Maybe there's at least one person like this in every family. Sometimes there are underlying reasons why people aren't talkative at the function. If you go to a party and one person just won't chat with anyone, they tend to get ignored. If that's what they want, that's what they'll get. This person wasn't about to ignore the non-speaker at this family party, though. It seems like this w…