STUPID MOM PROBLEM

Stupid problem with mom

So my little brother is depressed since I'm his big sis and brother can tell things to his sister that he didn't tell to his mom I I go to talk with him cuz he is 1 year younger than me I understand him more cuz we're both teenagers I know what he is going through but I didn't say mom isn't worried about him or doesn't feel him anyway she is the one who told be to talk with him in the first place but here we are she was listening to our conversation behind tye door and miss understand "ignore mom feelings ik u are worried because u see her worried ignore her feelings to focus on ur own so u can see ur own problem and fix it so u can study and she be happy at the end so it fine to be selfish in good way sometimes I went through this and look at me she isn't worried about me anymore" all that she understand it like "ur mom doesn't really feel ur pain she doesn't understand u at all" like wth ofc ik more how to make him calm down BECAUSE WE'RE BOTH TEENAGERS WE UNDERSTAND IT WE ARE KIDS WE UNDERSTAND EACH OTHER STUPID STUFF OMG...anyway she just entered to his room telling us "I'm not a stupid mom and listen mom always feels u don't listen to her I'm not the joker" yeah she literally said joker because at then end we we're talking about a comic and I still Don't know yet what's joker have to do with her she is just obsessed that ppl always talk about her..anyway we started to explain the miss understanding but she chooses to go to her room ignore us and telling my brother everything is fine and tell me that I'm the worst demon manipulator person like HUHHHH he even told her I didn't say anything bad about u when she asked him secretly on his room but HER BY HERSLEF KEPT DENYING AND SAYING  "NO NO I KNOW HER" NO U DON'T KNOW ME U DIDIER EVEN NOTICE I DIDN'T EAT FOR 3 FUCKING DAYS NOW IDK WHAT TO DO I DON'T WANNA DEAL WITH HER BULLSHIT AND IT NOT THE FIRST TIME