The father was a lord of some sort and was assassinated (probably by the Archduke) and framed as a traitor.
That is how the family fell.
As for the war? Who knows, maybe a power grab operation by this Empire?
The mom, we don't know much and that us because mc doesn't know much either. He's not just the protagonist but our guide in this story.
What he knows we know.
thats not necessarily true. the author could have included flashbacks or something involving the parents like i dont rlly feel as bad for him as i should because i dont know what the parents were like. it’s not like he was a baby when they died yk? at least show us some good memories so we have a connection to them like he does
the only thing i dont like about this story is the lack of proper world building. so far we know nothing about the mc’s parents besides the basics. we dont know the details of how the family fell, what happened to the mom, what the war was about, who the dad actually was (they treat him as if he were super important but havent explained exactly how), etc. these are things that should have been explained in the beginning but they werent which leaves us guessing