I'm fairly sure they know he's dead. If he was alive, he would have already made it back to them by then. Also, if you think about it, one of the reasons why the wife and daughter was unscathed was probably because they left the MC to go to the wife's parents, who lived far away from the main cities. If the MC didn't fuck up, and they didn't leave, good chance they were all going to die. Him fucking up and them leaving is what ensured their safety in the end. Tragic.