He's slow clapping the fact that they finally got together. Meanwhile he's over here past his prime he believes and still single and mingling often. Would su have known about the bullying? If he did I feel like his hands would be tied about trying to help aka bully them back since there's a chance they were too young to do that to and he'd just get in a lot of trouble. He'd try anyway and get creative. He'd also have been super protective (probably still is in a way) as well.