Worried and over thinking. This is with!

Hi , this is with regards to my brother who is going for his graduation studies in mangalore. He is been thinking a lot and is been depressed since sometime. He used to stay with me in Bangalore and I could see a change in his behaviour and was quite happy . But since we have come back to our hometown and parents decided him to send him to managlore he thinks a lot and is bent towards negative thoughts. I have taken a test consulted by doctors last time I can share the report if needed. Please help me cheer him up and make him have his confidence back. He is a smart kid and has friendly nature.However I am worried to send him away as he shall be staying alone in a new city. He has made journal where he has penned down his thoughts. I went across the journal and I m worried for him. Please suggest what should I do in this matter. I need to take care of this before his classes commence. He has been in this stage and has dropped out twice due to same issue please help me