Ahaana, 29, one of the two children of Dharmendra and actress-MP Hema Malini, welcomed a baby boy on June 11 with her husband Vaibhav Vohra.
"It is good that she has delivered a baby. I am very happy about it," Sunny told PTI here.
When asked if he has seen the baby, Sunny says, "I am happy for her (Ahaana) and the baby. I have seen the baby.... baby is good."
Dharmendra has four children from first wife, Sunny and Bobby Deol who are actors and two daughters.
About his father's (Dharmendra) health, the Sunny, 58, said, "We do tell him do this.. don't do this. But my father is an individual personality he will do what he wants to do.
He will not listen to me, you or anybody... he is that way.
But he is fine.. he is ok. He is looking after himself."
Dharmendra, who recently injured his shoulder, will undergo a surgery after the release of his upcoming film "Second Hand Husband" next month.
The 79-year-old actor was admitted to Breach Candy Hospital here on May 27 after he complained of pain in the right shoulder and weakness.