Sometimes, when you are brought back to your childhood by a moment like this, you realize how far you have fallen from that innocence.
Other times you realize how many people have taken that innocence from you and how little control that child had over their circumstances.
Look at the way he is standing before she tells him she recognizes him, arms crossed, brow furrowed, in defiance of the law. And then his brief, unbridled joy followed by complete collapse into anguish when his concept of the law is annihilated by recognition of someone from his past.
Maybe I'm projecting, but I think you can see the child he was for a moment when he is so happy to see someone from his childhood. And then he has a breakdown because that's not the kind of joy that he has been able to keep in his life, by his own actions or those of others who have taken joy from him.
I do hope that for whatever reasons his life reached this moment, he's received the support he needed and had the good sense make use of it.