Son Woong-jung is our boy Sonny’s, old man.
Wikipedia lists him as a South Korean former footballer who played for Sangmu, Hyundai Horangi, Ilhwa Chunma and the South Korea national football B team.
The YouTube blurb that accompanies this short film says, Mr.Son Heung-min and director [sic] son’s philosophy towards the education of the youth soccer player. He also tells about how he prepares the alternative school for the youth soccer player.’
There’s a detailed article about his father’s ‘interestin’g methods here.