The singer was admitted to Lilavati Hospital on Sep 23 after suffering a brain hemorrhage and a neurosurgery was also performed on him.
Singh was critical when he was brought to the hospital.
“We were told by the doctors treating him that this kind of bleeding could occur when a blood vessel within the skull is broken or leaking," said a source.
"The clot is removed after opening up the skull," said Dr Vishwanathan Iyer, consultant endovascular neurosurgeon, Kohinoor Hospital.
However, the hospital authorities abstained themselves from commenting further on the kind of treatment the Gazal maestro was getting.
"Singh has been operated for brain hemorrhage. He is stable. His family would not like to disclose more details," said Lilavati Hospital"s spokesperson.
Famous singers like Anoop Jalota and Pakistani singer Ghulam Ali also visited the singer at Lilavati Hospital.