On the witness stand, why was Casey Anthony's brother Lee such a bawl-baby about his sister having a baby?

The strange behavior of Lee Anthony, Casey Anthony's brother towards his sister did not seem normal when he broke down on the witness stand. It was not something a mature adult man would do but something a child would do. Why did he cry so hard and sob about not being told about his sister's baby shower for her first child? Didn't he have a life of his own at that time? Was he possessive or jealous of Casey because of his own inadequacies and/or insecurities or because of George and Cindy Anthony? How was his testimony supposed to help his sister Casey and her defense? What was his relationship like with Cayley, his niece before her tragic death?