Akshay, 44, along with his son Aarav performed the last rites of Khanna, who passed on Wednesday morning. He was 69.
"I always wanted to witness my father-in-law's superstar stardom during his hay days, thanks to you all I did, giving him a dignified funeral that he deserved. I appreciate your thoughts and prayers.
"Thank you everyone for your kindness and sympathy during our time of loss. Your thoughtfulness at this time of great sorrow is truly a comfort. Knowing you all are here helps," Kumar posted on his Twitter page.