Sad to lose another one.  John and Duane were close.  I remember reading of how Duane got the various Muscle Shoals guys to warm up to John.  Seems like Duane was visiting with John just days before he died. 

I had the opportunity to meet and sit with John Hammond Jr many years ago at the Keystone Palo Alto. He was play support for John Lee Hooker and Robert Cray was the opening act. I was sitting in that night with JLH and while just mingling around back stage during Robert Cray's set he approached me and said "Hey man let talk" and he took me into the dressing room and he just rapped with me for an hour...I don't remember much of what was said because it was 40+ years ago but I remember being totally taken in by his kindness to a young guitar player in awe of him. After Robert Cray's set he went on stage and at the end of his set he simply walked off stage gave me a wave and went out the back door. I hold that night as one of the most special nights in my career playing music. John Hammond Jr was a kind man who gave his time to me for no reason other than to be kind to me...RIP John I will remember that moment in time forever and I will take it with me...

I bought Duane Allman an anthology about December 1972. Still have my copy.