maybe I'll say play together.
I'm not a game addicted, at least not at this level (I'm 34 years old, btw). In the past I was into the Starcraft 2 loop, at least 2 hours at day, then watching matches on twitch. Then I stopped because, for me, was a waste of time, then right now I'm on game developing, because is more difficult and I get more satisfaction (but I have a work, so I'm forced to go outside!)
I'm not sure that could be right solution, but play together, into same room, help to understand that other people exists. And make breaks, drink a beer together, eat a pizza. If this work, go to a DOTA championship, with many people. I'm not sure you understand how big is the community around this kind of games (I mean, seems amazing for me!)
If your brother is at college and he's not a genius, he need time to study, then play DOTA. I'm asking you: how good are his grades ? In Italy is not possible to continue forever college without good grades, I think same everywhere, mainly because parents cuts money
So? So for me your brother is not crazy. He is inside a loop, but without his will, there is no hope. He must understand what he's right for him.
It's hard for me to write it, and for you to read it, I know.
It's same for every addiction. You, as brother, can be a good support for him to understand how much he is throwing into this passion.
For me, life is an hard way into find an equilibrium between the world, me, other people. In my opinion your brother's life is out of this equilibrium, because as human we are not able to live without friends, love and passions, or better, it's really hard.
A sister of my ex girlfriend 21 years, is in a similar situation.
It's all started when she finished the college. Few friends, no really "big" relationship with anyone. Then her parents don't force her to find a job.
So for the last three years, she wasted her incredible 18,19,20 and 21 years. I mean, it's incredible years for anyone.. but she don't do .. NOTHING.
She wake up every morning, watch tv, read a lot of books about vampires, eat, play video games (she was forced to use only one hour of internet connection for week, at local library), read, eat, watch tv, go to bad.
She's depressed, it's clear. After first year, her parents force her to go to a psychologist in order to understand why she don't want to find a job, a man, friends (like everyone else, one could say). This path go to nothing, in my opinion because her psychologist is not able to help here.
With my ex-girlfriend we tried first to propose here to go outside, but she don't like our friend too much and in particular she don't like to talk first. Then I've tried to help here with role-playing games.. but she didn't talk too much. Then she find her way in a local live role playing group (Vampire the masquerade one, btw).
It's a difficult path, but for what I know requires a lot of time.
Personally, my father told me in order to understand what is life, you have to earn it
(a bit of background. My father was born in 1938 and live after WW2 in Italy, with no father and 7 brothers.. so I think it's bit different for everyone)
So, using my father words..
1) let your brother play with DOTA for next six months. Work on relationship with him, be brother, together, even with little things (eat together, try to go outside, at mall, with common friends, make a small trip outside, ask his help with no pressure, invite women at home etc..)
2) if after six months it's not working, talk to him, try to understand why DOTA is soo much important to him. Don't put preconception. Just listen. Don't talk. Listen. It's soooooooooooo much important for anyone, even if you think your brother is crazy
3) ask for help. With parents, with common friends. Don't ask on forum. People around you can help you. Seems strange no? Trust me, people from your house, city, country can understand you and your brother better than me
4) If I'm your father for last resort, I will cut money. Without money, there is no internet connection, no food, no DOTA. Wake up brother, life is hard. But for last solution!
wall of text, right ?