Here is a little story about him:
When the tracks for Prem Rog was being made, the male singer originally was supposed to be Anwar. (Anwar is a Rafi clone, for those who don't know.) He was a pretty good Rafi clone, but he had bad work ethics and unprofessional behavior which turned off Laxmikant Pyarelal. Anwar only had one song in that film. Suresh Wadkar stepped in for the film and Raj Kapoor was very impressed. He was so impressed that he assured him playback singing for any RK production.
When he was alive, this was true for films like Ram Teri Ganga Maili and Henna. After that, RK banner faded away in the wind.