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).
Mayor. "Hermano Mayor" can mean "big brother", "bigger brother" or "older brother."
big brother
You would say "brawd fawr" in Welsh to mean big brother.
It means big brother in Hindi
It means big brother in finish
It means big brother
It means that Gale is like her older brother
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
Because they are dumb and have nothing else to do.