In Malayalam elder brother is called in different names like Chettan, Jeshtan, Ettan, Annan.
Your brother in Malayalam is "നിനക്ക് അന്നയന്" (ninakku annāyan).
In Malayalam, you call a younger brother "Chettan."
The Malayalam word chettan means elder brother
Little brother
You say "ചേട്ടന്" (chettan) to refer to an older brother and "അച്ഛന്" (achchan) to refer to a younger brother in Malayalam.
Aliyan
big brother
In Malayalam, brother-in-law is known as "അനുരാഗന്" (anuraagan).
anoop
You would say "അവന് എന്റെ ചേട്ടാണ്" (avan ente chettan).
little brother