
So let me get this straight, Sunbae recorded the videos of his previous relationship for private use. However Mr. Cheater created the voice recording, and this was blamed on Sunbae, with Sun Hwa taking the brunt of the humiliation?

I think this is it yup.
But... its seems that sunbae revealed the videos of his previous relationship. And I didn't understand why

I disagree with a lot of the comments about the mother here. She believes her child is the good one, and so she is more inclined to faults others for anything bad that happens. Haruki pushed her buttons and so she reacted angrily, because she thinks that Hikaru is becoming weird because of Haruki and because Haruki insulted her. There isn't any explicit evidence about Haruki's "bad influence", but that's how she thinks.
But yeah, Haruki definitely insulted her when instead she was indirectly giving him a way out of this mess. Stay away from Hikaru? What could be better than that?

daaaaanggg you in danger gurrll.. it aint fashionable to side with a female character in a yaoi manga. guy can be a rapist and still have fangirls but not women. even slightly annoying ones get burned at the stake. this mother totes deserved to get killed to them.

you see how the fangirls here act. not many called out the dad. only the mother is evil. in yaoi, men get away with a lot.

The father isn't going to step in because he is rather clueless about the whole situation, instead thinking everything as if it was business as usual. It seems as if his main source of family information is anything that he can directly see, and the information provided by his wife. The mother, who is more concerned about this issue, will make or break the qhole situation.
Unfortunately, she is far more biased towards Hikaru. Meaning that this will probably end in tears. Props for her for directly reaching out to Haruki. If she is a responsible mother, then she will continue this action of digging out more information and apply very heavy pressure on Haruki to clarify what he meant about she not knowing anything about Hikaru.
Unfortunately, given the history of mothers in yaoi, this will probably end in more tears for everyone involved and more injustice needing to be avenged.
His hair looks fine after the haircut. So whats up??????????
Σ(っ°Д °;)っ