The Judge didn't NEED the school counselor to testify, had apparently heard enough to make a decision. No need to waste more of the courts time. You got custody, so SLIM chance you would LOOSE custody, at least no time soon, and not with-out a HUGE change of circumstance. So just breath.
As for your older child watching the younger ones, I wouldn't sweat that. First, the child is 13, plenty old enough, and legal age (at least in my state) to babysit his younger SIBLINGS. If he is responsible and kind to his younger siblings, why shouldn't he? You are all a family and need each other. You are showing your son responsibility as well as the importance of family. You have a long road ahead of you, I wish you and yours the best.
Stand up for what you believe in, even if you are standing alone.