Comment by ShojoTomodachi on I read too much

So the way I see it is that he's not cruel or anything. He has always been kind, only teasing him sometimes. So he is not happy because he's sad.

Instead, he's happy because the tears mean that he holds a place in his heart. Someone cares enough about losing him they they'll cry about it. 

He was incredibly abused and had no one in his life that cared that much before this. So that's why he was happy about the fact that he mattered enough to someone that they'll cry over him.