I am very sorry to hear of Jim's passing.
Not only did he write numerous books that brought enjoyment to all who read them, but most importantly he recorded the history of an era (basically the second half of the twentieth century) in PNG that would otherwise probably not have been recorded.
In PNG nowadays there seems to be almost a policy of ignoring the past. Whether this is a futile attempt to erase the memories of a colonial era, or simply a preoccupation with the present (and what can be scammed from it), I don't know.
I live in hope that future generations in PNG might wish to know more of their nation's history, and but for the efforts of Jim Sinclair (more of a labour of love than a commercial success), this history would be forgotten forever.
May he truly enjoy peaceful rest.