For all you weebs whingeing about the mother ( or lack of her presence )...
Just imagine this is a japanese comic, portraying a very japanese noble household with some semi-european slap stuck on for flavour, dealing with the ascent of a male member and heir of that noble household.
Now imagine the actual place of the mother in the story, considering she is the First Lady of a japanese noble household, and when/where her actual job/position would tie into the story as it is presented...
Now stop whingeing.