There was a time when Ume started to starve herself, she lost so much energy she even got hurt by a low ranking demon, Gyutaro desperately wanted to do something about it, he was very worried about her, first she calls him by his name instead of onii-chan then started to distance herself from him and now this, but he didn't knew what to do, he didn't even knew why was she acting like this, so he asked Douma, who also noticed her strange behavior, for help, he was also very worried about Ume so he confronted her for starving herself and not having healthy habits since that is not a hashira's behavior.
Even tho Ume didn't tell anyone what was going on with her, not even Gyutaro, she still told Douma because she knew he's the only one who would give her the answer she needed to hear the thing is... that while growing up Ume started to realize that her brother wasn't really her brother, she started to realize that she's his half sister and that made her feel really bad with herself because he was out there in the battle fill giving his life for someone who wasn't even his actual family, but she started to reconsider things when Douma told her; "there's more in family than blood ties Ume, if that wasn't the case then technically people who are married and have children shouldn't be call family as they don't all share the same blood.
Ume... I had parents and Gyutaro and you had a mom yet neither of us ever felt like we had a family until I met Inosuke and you guys escaped from your old village, so Why now act like he isn't brother, the same boy who always loved you was always willing to give his life for you and you were always willing to do the same for him because love him as much as loves you?"
