There is a probate on Archway for him. He died at Neiafu, Vavau on 1 Nov 1899. I have transcribed the European cemetery in Vavau, and he is not there, unless he is in one of the unmarked graves, but there are other cemeteries there.
The will is held at Archives NZ, Auckland.
I doubt he will be registered in the Tongan deaths, as they are mainly of Tongans, not Europeans.
I think the will is your best source of information.