Hrithik, 41, who suffered personal setbacks in the last two years including a brain surgery and his divorce from wife Sussanne Khan, called his actor-turned-director father "an amazing human being".
"My father's journey will always inspire me till I die.. his will to bear the extreme conditions of shooting to facing tragedies like having no hope. He has an incredible journey," Hrithik told reporters on the sidelines of IIFA 2015 here.
"My father believes in the saying that 'men don't cry'. My father has been different. He can't express his love. But my sister decided to write about him after 25 years to change it by expressing love for him. She did a lot of research," he said.
During the event, Hrithik also spoke with Sunaina, who is in India, via video chat.