...he isn’t overwhelmed by emotions but they seem more intense or bigger. He is also very empathetic and quickly picks up on other people’s emotions and feelings too.
Maybe he's a Highly Sensitive Child. Have you read up on that trait? Your description sounds very familiar to that personality. Elaine Aron's book has been a real eye-opener for me on that. Something she said about kids like that is they don't like scary or violent movies and tend to hold back when faced with new situations, often wanting to observe over and over before going for it.
That he stands in line and tries to be like all the other kids is part of some HSC's need to please. If they sense you really want something of them, they will deny their own feelings on it to some extent until they back out or have a meltdown.
