He couldn't allow himself to cry. The tears pooling in his eyes as Rossi spoke to him were... exhaustion, fear, regret.
He could not allow himself to cry because the pain, the physical pain would be too great.
He couldn't allow himself to cry not because showing emotion was wrong, or not because he didn't feel. It wasn't because he was detached, either. Detachment was for the professional part of his life and this... was personal, the second time his work had crossed that line. His job had taken Hayley away from him and now his son, too.
He couldn't allow himself to cry, not now, because if he did, he may never stop.