@terinayaya
His father wasn't interested in his sons disapproval and already spread around that they're going to get married. Talk no jutsu only works on enemies in manga. You think most people are able to talk their way out of an arranged marriage? The amount of married couples who would disagree with that sentiment working out even in modern day is quite substantial.
True, he perhaps could have convinced his sister first. True, perhaps he could have spoke to his mother who seemed to be leaning towards listening to him. But his sister would have stabbed him cuz yandere. And his father would once again just ignore mc's mother.
I don't disagree with you at all for an irl approach, it just wouldn't work out as well as we'd hope in this manga imo.