"He (Rajinikanth) is recovering well. He is doing fine. He is responding well to the treatment," he told reporters here.
"Doctors have found out the root cause of his (Rajini''s) trouble. It is something that can be reversed," Dhanush said.
According to him, the 61-year-old actor is cheerful and is "in a mood to shop. He eats whatever he wants.
"We hope he will return (home) in a week or 10 days. If we do not return, that means we are on a holiday (in Singapore)," he said.
He dismissed as a joke reports that the actor required kidney transplantation.
"There is no kidney transplant. It''s a joke."
Rajinikant, who was flown to Singapore on May 28, was admitted to the Mount Elizabeth Hospital for "rest and rehabilitation" after discharge from Sri Ramachandra Medical Centre here. He was admitted to the SRMC on May 13 for respiratory infection and other problems.