Responses
I don’t think he knows about the accident, but I could be wrong. I thought Taekyung was mad BC Heejae had been in love with him and when they parted Taekyung regretted it. And he assumed Heejae would have some sort of lingering emotion attached to him as well but when they met he realized Heejae had completely moved on and forgotten him.
I’m pretty sure Heejae only referee to him being dumb now, but Taekyung doesn’t know the full story or that he has amnesia yet.
A lot of people are saying that someone needs to tell Taekyung that Heejae has amnesia, and I could be understanding wrong, but I'm pretty sure Taekyung knows about Heejae's accident, because they talk about it in a memory in a previous chapter, and how Heejae doesn't want his memories because it doesn't gurantee his intelligence. I think the reason Taekyung is mad is because Heejae has forgotten about him, even though they met again after the accident.
Again, I could be wrong here, so I'm gonna hunt for that chapter and reread it.