I hate my brother so much , he know my little secret ……

So I am a 24(F) still studying in a university …I have younger brother 21 who constantly gets on my nerves he thinks he is the smartest parson in the room but in reality he is just an insecure man who couldn’t take accountability. Last year he got to know about my boyfriend cause of stupid ipad login , he save my pics with my boyfriend in his phone and constantly taunts me about it , infront of my parents ( they don’t know I have a boyfriend 😭 and I just can’t tell them cause they are typical Indian parents who will panic if I told them I talk to a boy , I would like to eventually tell them about it when I get a job )
I feel so irritated and helpless when he taunts me in his own way . If I make him upset by telling my opinions he blackmails me by saying tera bhanda fod donga …. And the irony of this is that he himself is not an innocent guy he drinks smokes goes to parties and talks to girls without my parents knowing a single thing. I am so fucking tired of it . I stopped talking to him entirely , even then he doesn’t stop saying such things . What should I do ? what can I even do? I hate him the most