no he knew long before that
A long while ago, Yiyun's cousin invited him to a party where she introduced him to her grandparents, then not too long later he finds out when he's visiting the grandparents house bcuz they have a pic of his mom, n then later his mom brings him to the grandparents house again and they tell him (i think, its been a while so i might be a bit off)
Yi Yun’s uncle revealed the truth to him at chapter 124.
must have slipped my mind but do you remember the chapter where his mom brings him to their house id like to reread
so yiyun found out he's part of the he family through the media statements?? There was no face to face reveal or did i miss something?? HELP-