He was 76.
Sadhu breathed his last at the Sion Hospital, where he was admitted yesterday for a heart ailment. He was in a critical condition and put on ventilator support in the Intensive Care Unit (ICU), hospital sources said.
"He was suffering from cardio myopathy," Dr. Jayshree Mondkar, dean-in-charge of the hospital, said.
He was known for his work in Mumbai Dinank, which was his first novel, and the book Simhasan, which was adapted into a Marathi film.
He was conferred with the Bharatiya Bhasha Parishad, N C Kelkar and Acharya Atre awards also.
The veteran scribe wrote on the rise of Shiv Sena, the Vietnam war and the Chinese revolution, besides several short stories.