"I would like to see Gibbs explain why he had to leave the courtroom and why Felos was allowed to stay."
Me too.
I think I know the technical answer. Gibbs is representing the parents of Terri, not Terri. It is a charade for Greer to even pretend to let him make motions and participate to any degree, because Greer has made it plain that he does not recognize any standing in the case other than himself, Felos and Michael. He is "allowing" Gibbs to participate, up to a point. But when they held a conference of the parties, Greer excluded Gibbs because he considers him not a party to the case. Technically, he is correct, but only because he has ruled that the Schindlers are not parties.