I'm going to disconnect my stepbrothers internet
What is your reason for wanting to disconnect your step brothers internet?
Yes, he is being so fucking annoying with online gaming
I'm sorry he is annoying you, but you have no right to disrupt his leisure time because you don't like it. The games and internet are his, and you are just worsening your relationship because you prefer to act now and think later or never.
He should play with us if he wants to go home and play with the internet.
Tampering with his possessions will most likely just give him reason to act even more annoying. If you want to resolve the behavior you are better off being honest with him about how it makes you feel when he acts this way.