He didn't understand, he thought when he was acting he just being the same as everyday that's why when he got asked by his friends he's now understand that it's affecting everybody since he now have "complete soul"
He is socially delayed, fam. Someone who is socially delayed won't be able to self analyze themselves on a NORMAL spectrum cause he's not normal. And because he wasn't taught how to communicate his intentions he assumes people will ignore it anyway based on what he's already been through. He still doesn't think people's interest in him is authentic because they always reverted back to hating or ignoring him. To sum it up the kid is layered with trauma and neglect so much so that he experiences derealization as his personality trait. It's take him some time to adjust to normal social behaviors after everything he's been through.
he could have explained earlier that he was acting; he treated people badly and thinks everything would be normal. He was lucky that they still wanted to talk to him instead of ignoring him. Not judging him, because it's understandable.