I believe someone else testified to being her best friend. But even if that weren't the case, I'm curious what evidence, if any, was introduced to back up the sister-in-law's claim of friendship. Things like photographs of her with her sister-in-law, letters, autographed or personalized gifts, testimony of others about their friendships, etc. If you know of any, I'd like to hear of them.
Then read the text of the case. Obviously, it was sufficient for the Judge.