So upset what would you do?

Charlene • Create your own happiness 🥰🥳🤩😇🥰
So today my 15 year old brother guidance counselor called me to tell me my brother has missed a month of school, that when is he coming back?. I told her I was not aware of that, I currently attend University and don't live at home. My brother is an All Star Student, he is extremely smart, he scored high on the MCAS. He got to travel the world already. He is in honors classes, straight A's student. Now he has all F's from not showing up to school! Each day he missing is an F for his absence. He has so much potiential. I was so upset and terrified this is not like him at all ! 
I called my mom to tell her the guidance counselor called me and I was so upset with my mother it broke my heart. I told her what's going on with my brother? She said he's been sick. I know we both haven't healed from our car accident from a year ago he still suffering some of that pain. I feel like he's probably been bullied at school or something as well. I love my brother. My mom makes me feel sad. She told me she been going through a lot too. We all been going through a lot. Grand father just past, my father left the country to handle business. I'm pregnant, I'm dealing with my injuries still. She makes me feel like she hasn't shown us the love we deserve. 
Should I take over? Or let my mom deal with it? I'm going to most definaftely talk to my brother about what's going on. Any advice on how to approach this, I don't want to discourage him.