"Hilo, boys" is mentioned again here. Unfortunately the context in which it is set in this fictional account seems pretty shady. The author may be just transposing a known chorus to a fanciful setting.

1876        Unknown. "The Arab Wife." _Chambers's Journal_ 4(675) (2 Dec. 1876).

In the excerpt, the narrator, an Englishman coming from Calcutta, has somehow found himself in a boat off Malaysia with some Papuans. There is some sort of boat race.

So whilst Abou was arranging the oars, I got a lot of Papuans, and began to teach them a medley. I could not for the life of me remember the words, but the chorus went: 'Hilo boys, hil-lo !' The rest of it is unimportant, and can be supplied with any gibberish ; so I filled in with Papuan, and taught them to pull strong and slow to the words 'Hilo boys, hil-lo!' ...
We were last, singing our ' Hilo boys, hil-lo !' keeping about a hundred feet in rear of old Tamula, and going so beautifully that Abou was in raptures, and whispered to me that we could win....