A trial for a fatal brawl at a youth football tournament in Germany that left a 15-year-old boy dead began behind closed doors at a court in Frankfurt on Thursday. The underage defendant is facing charges of assault resulting in death over the brawl. The parents of the victim, a boy from Berlin who died after receiving a blow to the head, are co-plaintiffs in the case but will not attend the proceedings, according to their lawyer. “The reason is that every time they talk about it, Paul dies a second time. They wouldn’t be able to cope emotionally,” said the attorney, who appeared in court on t…