You can consult a psychologist about it. It would be of great help. Don’t feel shy it’s completely okay to talk about mental health. They could suggest you methods which could be really useful in eradicating this addiction of your brother. Seek their help. You can consult them through fortis 24×7 help line no. (+918376804102) . They have come out with some great initiatives such as digital detox where they spread the message to unplug and switch off all technology and devices for 4 hours a week.

It’s okay you know, sometimes you could just relax first, and then think about it. Some children listen better when we talk to them in the ways they prefer. They’d listen to you this way. Be firm in what you say, but be friendly with him. let him understand why you’re doing this, it would be better and more effective to keep him away from gaming :)

find him ways of being indulged in constructive gaming.

Just practise what you want to teach him yourself. He will gradually learn it

You have no idea how similar our circumstances are!! My younger brother is the same and nothing seems to work. I guess we can’t do anything until he himself realises it’s wrong. Hoping for the best

Hey. I am glad you are worried and are trying! I hope its just a phase and he realizes the futility of it soon. Stay strong!

Maybe you can try playing with him outdoor games. Just don’t ask him to play outside but play with him too

True, even my siblings are the same. This generation is becoming aggressive and online gaming addiction has become a major problem for them. They are influenced by internet and online gaming alot, that they don’t even think for their future purposes. 
I think we should try to talk with them and make them explain the disadvantages of this kind of addiction. They will realise it.