We're thinking late 50's is a pretty normal age for someone to die. People do sometimes make it past into their 60's, but they are considered elderly by mid-60's. Anyone who lives into their 70's is a legend, basically.
I would say Najam is a little south of middle-age but definitely still healthy and able. However, he would probably have already begun scoping the younger generations for his apprentice, though it's not desperate yet if he hasn't found someone fitting.