It very much depends on the behaviour displayed.
If, for example, he insults or otherwise verbally abuses you, you can at first ask him politely to stop. Most of the time, if you respond in the same manner, it will only provoke more abuse.
If he doesn't stop, or if the abuse is not only verbal, but also physical, inform someone with authority of what is going on: your parent(s) should be able to protect you from harm.
Only if the situation is very serious (you have good reason to fear for your health and/or life), call an emergency number (in the US it's 911) or the Domestic Violence Hotline (1-800-799-SAFE).
If your brother makes fun of you, either laugh or ignore. His goal is to make you angry, he wants you to be angry and yell. If you yell or show action he will do more and laugh and get happier. I have a mean older brother and all he wants is to make me angry. If he tries to hit you just pretend you don't care and if he does, tell your parents. Don't tell your parents every single time or else he will start making more fun of you such as tattle tale!
Give him a taste of his medicine (hit him back if he hits you) when he goes to tell your parents act innocent.
Mayor. "Hermano Mayor" can mean "big brother", "bigger brother" or "older brother."
big brother
Reference to novel 1984 in which big brother is a collective name for the totalitarian government.
It means big brother
It means big brother in finish
It means big brother in Hindi
It means that Gale is like her older brother
nii Chan mean big brother in Japanese
Tell you brother to knock it off. Tell your parents.
In texting GE means: Good Evening.
I love [you] big brother.
The best big brother