Responses
This secret doesn't feel too unreasonable. Like really what good will it do him to tell him something like that this long after the fact.
I don't think he'll tell him.. That's not how plot devices work :) He'll find out.. and I find in lots of Asian entertainment that blame for some thing ,even someone else in the family perpetrated, will fall on one of the leads characters to create the riff... even if it was a long, long time ago by a grandfather far far away:).
the stumbling block that will happen in their relationship. Secrets are always found out.