Siddarth Shukla is a BIG BULLY. He is no one's frnd.
He says the same dialogue to all "Tere paas demag nehi hai. Tu demag use maat kar." He thinks he is the only "Demagwala admi..............baaki demagless."
So he was never Asim's frnd. He used Asim like a slave. When he refused..........he beat him and still doing. He did the same with Sana too. But she is the one who is tolerating all his craps.
It is not SHukla who is tolerating...............it is Sana who is tolerating all the craps of Shukla. In fact she is defeating Arti too.