My brother is stealing money from us and spending it on his girlfriend.

Some background context: I belong to a family where I'm the first generation graduate. I work in IT and earn decent money so I can live a comfortable life. Due to some recent career events I have recently relocated and am now living with my family. I used to live away for sometime(around 2 years) My brother (5 years younger than me) and me are like best friend since I can remember we share everything including me having my crush on someone him having his first break up and so on. Things changed since I moved away to a new city we started having less and less conversation, I still believed that I know him enough and I can trust him with my life. About a week ago my father asked my mother if she has accidentally sent money somewhere? He noticed that the account has some balance mitmatch. He went ahead and got the bank statement as my mother also had no idea where the money went. As we checked the bank statement turns out it was being transferred to my brother account using different UPI handles and different UPI apps. The amount here was not an issue to be fair the breach of trust is. It was enough to buy a mid range phone. My father was convinced that he's either stuck in some scam or he's been using those gambling or betting apps. My brother recently told me that he has this new girl he's dating and I have been getting not very good vibes. However I never thought he would do something like this. He's not working and is performing really bad in his studies to be fair I had always been on his side and stopped my parents from scolding him for poor grades etc. Because I know it doesn't matter that much in long term. Now as this all unfolded I understood that he's spending the money on his girlfriend. My father checked my brother bank statement and found transaction to various *10 min delivery* apps and some accomodation websites. I felt really sick 🤢 Not that he's spending the money on accommodation but that he's doing this for over 2 months now. I had no idea what's happening in his life. I didn't know how or what to do in this situation we confronted him. My parents confronted him as they wanted to know why he's doing all this? His answers were obvious not very straight forward he was guilty and he was saying stuff like "dost ke khrcha hogye" "idhar udhar khrcha hogye". There was huge drama etc in the house after that. I explained to parents that we should give him another chance and we asked him to stop talking to the girl. Stop using the social media for a while and just focus on the studies. I'm even in shambles while writing this. We share the same room. So he's doing a video call with a girl in front of me! He has a exam in 2 days and this is after all of this happened. Now I don't want to involve my parents in all of this because they will lock him in a room or go to extreme measures like sending him to our village. I asked him to stop talking to the girl as it's not a good relationship for either of them. I seriously don't understand how can anyone not suspect that your boyfriend is spending thousands and they don't earn? I thought he would listen to me and stop talking to her. Now I don't know if it's the same girl or someone else. He's still using his phone after a week to him everything is back to normal. To me nothing will be normal. I asked him to delete/deactivate instagram for sometime focus on himself. I have asked him thousands of times and he's still doing the same thing. I have lost all faith in him. And I don't understand what is happening he in early 20ies he's jobless he's practically just wasting precious time and effort and he's just ruining his life breaking the trust of his family. I have tried to explain him again and again that stop doing this he agreed everytime and keep doing the same stuff We have shared everything he was my best buddy my best friend and now I don't know if I can trust him or not. The money he spent was send by me to my mother from my savings as I saw gold rates going down and asked her to get something. I had to take loans to complete my graduation. My father has practical zero wealth as he spent everything trying to make sure we get the education and whatever we need. I don't understand what went wrong. And what can I do now. Note: This is a temporary account I created as I'm a long term reddit user and I wanted to vent out.