I have a family of three siblings, with the eldest serving in the military when their parents are killed in a car crash. Assuming the eldest wouldn't be released from the military to look after his family, the only other family is a sister on the mother's side, who has her hands full with a family of her own. Would she be expected to take the two younger kids in - they're roughly 13 and 6 at this point - or would they go into foster care?
Secondly, I have the eldest brother being dischared from the military on medical grounds some years later - nothing too debilitating for civilian life but something that would stop him serving - so would he be facing much legal trouble/red tape to get custody of his siblings? Middle child is nineteen so not really in need of a guardian anymore, but the youngest is only twelve.
Any help is much appreciated. :)
ETA: As apparently I deleted the time period by mistake, it's set in modern day Japan, for clarification.