1. To resolve his problem, I would advise to take up a sport, better if it is in a team. I think it could be positive to take up a challenge, to increase his motivation and to meet new people.
2. I agree that Net addiction resemble each other addiction. It is an habit which you are psychological dependant on it. All addictions have the same features: compulsive engangement and the guilty feeling.
3. Yes. Nowadays, the media are very important in our social life. Many people feel lonely and depressed, even if they are surrounded by people. Our society is becoming more and more selfish. Many people live an unreal life on the internet. They try to avoid the reality with unreal friends.
No, it is not an invention.
4. I use the computer everyday, mainly for work, for searching information. But sometimes I also use it for booking hotels or flights. I have to admit that I am not keen on computers or technologies. I wouldn't mind to live without a computer for a while. It would have a beneficial effect on me, I would feel more relaxed.