Aadesh, 48, has been in the Kokilaben Dhirubhai Ambani Hospital in Andheri for the last 45 days for treatment.
"Dear buddy Aadesh, I am devastated at hearing about your condition... Can't come to terms with it. May God help you ease your pain," Rahman posted on twitter.
Aadesh's colleagues from the industry including megastar Amitabh Bachchan and superstar Shah Rukh Khan are keeping a check on his health.
People from music industry like Shaan, Sonu Nigam, Kumar Sanu, Alka Yagnik, Udit Narayan, Shekar Kapur, Govind Nihalani and Poonam Dhillon visited him in the hospital.