It does seem he has deeper connections with that drug. Might be..
Idts. Pretty sure hes also looking into whos making it.
When Jaeyoung goes to the doctor, it is mentioned, in what I think is a medical conference, that the drug was first developed in Brazil, and now it is revealed that Happy was raised there.
I assume he may have come across it when he lived there and was aware that they wanted to expand the market to South Korea as well. It would also explain the trap his noona mentioned.
Was Happy involved in making the drug somehow?