He Fell Into Something Like Depression

Hello! I'm a girl of 14 and my brother is 17. A few days ago, while watching TV alone at home, he came home very nervous. He began to collect the belongings of his girlfriend, with whom he had been dating for two and a half years, without saying anything. I asked him what was going on, but he didn't answer. He started swearing under his breath, then sighed, sat down, and suddenly cried. For the first time since we were very young, I saw him cry. I went to him and hugged him, stood there for a while and waited for him to calm down. I asked him what had happened and he told me that he had already seen his ex-girlfriend kissing a boy she introduced as a close friend. This was, and still is, the girl my brother loves very much and is ready for anything for her, and for that reason he has now fallen into something like depression. He's an athlete, but he doesn't go to training anymore, he hardly eats (eats once a day), does not go to school because they are in the same class with the girl in question, does not go out at all and even sleeps for 2-3 hours. In the evening he just stays for 5-6 hours, wanders from his room to the living room to smoke a cigarette and back to his room several times a night. He goes to bed around 5: 30-6 and gets up at 7: 30-8. He doesn't talk to anyone or anything, he spends most of his time in his room. So my question is, is there a way to get him out of this state? Can I tear his thoughts away from the girl in any way? I want to help him because this is not my brother who was before. he walks from his room to the living room to smoke a cigarette and back to his room several times a night. He goes to bed around 5: 30-6 and gets up at 7: 30-8. He doesn't talk to anyone or anything, he spends most of his time in his room. So my question is, is there a way to get him out of this state? Can I tear his thoughts away from the girl in any way? I want to help him because this is not my brother who was before. he walks from his room to the living room to smoke a cigarette and back to his room several times a night. He goes to bed around 5: 30-6 and gets up at 7: 30-8. He doesn't talk to anyone or anything, he spends most of his time in his room. So my question is, is there a way to get him out of this state? Can I tear his thoughts away from the girl in any way? I want to help him because this is not my brother who was before.