SidG and Dilbagji's relationship was special and like a father and son. Very different from Sid's relationship with his father. Dilbagji saw the best in Sid and believed in him. His way of talking to Sid was always encouraging him to be his best vision, because he sees Siddharth's heart.
The way Dilbagji would clean Sid's hand was so beautiful. It was like he was patching up his wounds.
Beside Mummiji, Dilbagji filled the void in Siddharth's life and both relationships should have been explored more in parallel with Siddharth's past. That would have been wonderful.
It's not like SidG's father is a bad father. He just made himself busy at work, to give his son a better future or maybe because he didn't know how to handle the loss of his wife or to be a single father.
Yes, he neglected his son, wasn't there physically or mentally, but he loved his son.
At this moment Siddharth's father has given up on his son, is frustrated and feels helpless. He doesn't know how to handle his son anymore or motivate him the right way.
It has become too much for his father and is not listening to what Siddharth has to say or feeling his son's pain. Likely because Sid at times creates a story "white lie" to get out of a situation, just like kids do.