I honestly think the mansion lord is doing things his own way and taking certain steps at a time to up-root the "evil nobles" and such. The steps that he's taking seem to be that way anyways, I can kind of see what's going to happen next, but that's if he's a good guy.
Like maybe he helped the teacher escape or the Lin Hong's fathers death was part of something bigger and the mansion lord actually couldn't help so instead he went to Lin Hong's father and told him that he couldn't help, but he could he him a quick death rather than be used by the "evil"... Hell I could be completely wrong and he's just a bad guy that let his general rot in prison/die, it's just that's how the writer is making him out to be that kind of person - so far. From my point of view anyways.