Thats highly possible.
But then again considering the start of the game shows the MC after a drinking bender and one night stand.
And we find out he hasn't seen his sister in a while plus he internalises all his feeling what make you think they would know if he was just selfdestructive theres a chance his friend would let his sister know but if he turned suicidal thats a diffrent issue .
However if he did just turn suicidal being that he do's keep his feeling bottled up.
Its more likely that like in a lot of RL instances the first his friend and his family would know about is when he was found dead.
Which kind of makes coming clean then both pointless and impossible.
Except in the daughters case but are you really gonna tell the daughter her daddy killed himself because of the lie you her mom and the rest of your family made up to keep him supossedly safe while at the same time keeping them apart from each other?.
Just Sayin could happen.
Well while the mother wouldn't say, all it take is one time drunk Aunt or Grandma to spill the truth out, Deb or the MC's mother could become spiteful of the fact Marie screwed over the MC and basically drove him to kill himself, so they might decide at one point, during a moment of weakness to spill the truth, which wouldn't lead to a better ending for the father and daughter, but who said vengeance is ever about making things better.
Also I think the whole accusation about the MC keeping everything inside is more a claim they make to justify having came up with the plan than necessarily the full reality. Because his course of action wasn't to their liking they sorta put the blame on him keeping shut, I haven't seen any indication to really show their accusation is right, its not like either people can be expected to blather about their every little state of mind, its really a crappy tendency to blame people for their problems and the fact others don't have the empathy to pick on said problems.
I mean they accuse him of not being communicative enough because he didn't talk to his wife about the incestuous affair he had with his sister... oh really? You mean most people would talk to their partner about the fact they had a affair with one of their own siblings? Strange, pretty sure 99% of people would keep their mouth fucking shut about such thing, and its not due to a lack of communication so much as keeping silence over doing something very much taboo that might destroy their marriage. But because him keeping silence in that case was inconvenient they call it him having poor communication, similarly because they didn't like his course of action of taking a fall for the sake of trying to expose the corruption amongst his government and military covering atrocities, he get blamed over trying to do the right thing. Isn't hypocrisy just great? Blame someone for not listening while not listening themselves.
When mc's backbone will grow ??
Never, its a plot device to help grow the harem by having him take the blame so the women can stay largely blameless so you can be justified in banging them later on. I mean sure in the eyes of players they might not be as much without blemish, but in story its meant to keep them fairly clean.
Plus you see it in the latest update, the story literally stomp over the first attempt to have your MC get a backbone and the MC is pretty much browbeated back into the previous status quo. Heck earlier an attempt at rebelling against a course of action would have a early game over by having people killed. This story is streamlined in one direction and any deviation is countered either by an instant game over or by effectively just ignoring the choices the player make.