Or, alternatively, you could apologize to your brother for the pranks, stop escalating the mess, and ask him again what he did. It's possible he was trying to cause you a little problem and ended up causing a major disaster. Or it's possible that the thing can be easily fixed. Have you tried just powering the phone off and restarting it? Often that will clear up temporary problems. Worse come to worst, you can do a factory reset, which will mean reinstalling your apps and setting up your configurations again.
Of course, I don't know the relationship between you and your brother. Maybe pete's brand of ever-escalating vengeance would work for you. But do you have any idea how many people in their 50s and 60s have siblings they haven't spoken to for decades over stupid stuff like this? Maybe it's time for a truce.