How can I figure out someones name, from the internet?

[Tj]

Sounds creepy huh? Well my brother has recently engaged in an online relationship, it was sad at first but now it is simply pitiful! He is literally LITERALLY texting this person he is convinced is a girl every 5 seconds, he took less hours at work to spend online time in battlefield and text this person. I believe it is a man, what girl spends 12 straight hours every night on battlefield 3??!! If this person is a girl she probably looks like Shamu. My mother feels bad any time she trys to do anything about it. Lord knows what they text. My brother used to like the military and listen to ACDC and Van Halen, now he is always wearing black, wants to paint his room black, is obsessed with dark things and listens to Black Veil Brides. This has gotten way out of hand and I want to prove to him everything is not what it seems and end this stupid bullshit!! I need to find out who the person he thinks he's in love with really is. As soon as I find out Shamus PSN id i am going to figure out his/her real identity. I need help, I am good with computers and a pretty smart guy but not that good. The main reason I think it might be a guy is because plenty of weird men do that and when I was younger I did it too......but only for fun.....to mess with people....I hate myself. Okay to summarize, how can I figure out this lying motherfuckers name.
To tracie who answered, I am very pretty good with getting IPs But I never know when he is online or just with that person specifically

[Tracie]

If you have there name try running it through search on facebook
.You would be suprised the info you can get from people off of facebook .But it will have to be the right name.Or get a program were you can get the ip adress comeing from wht ever pc or tablet or phone they are use3ing and use a trace .That will give you location also.