First, read this.
It's Paul Wheaton's hugelkultur article. That should give you a grounding, and enough information to ask the right questions.
Next, you can look through the hugelkultur forum here on permies. You just posted to it, so I assume you know where to find it.
Another consideration is that chippers are great at making mulch out of tree scraps, and that hugelkultur involves larger, whole-log sized pieces, large branches, whole trees, rather than homogenously-sized tree bits. You want the size of the whole wood pieces on the bottom for structure and stability over time, as the increased surface area of chips will mean that the piles break down faster.
The other direction in which you could go, if your mate is really keen on fire, is to get him to learn how to do an outdoor pit-burn in order to turn his burn pile into biochar, that is, activated charcoal that becomes inoculated with healthy soil organisms and improves the soil structure and health. You could quite literally excavate the pit trench where you want your hugelbeet, place the pile in it and top-light it, adding fuel as necessary to keep it producing char and not ash (it's a whole process, and somewhat involved, but right up many pyromaniacs' alleys; ask me how I know).
This would have benefits in your hugelbeet apart from the biochar acting like condos for your soil life. Biochar doesn't degrade, as it's just an open-pored carbon matrix, so it can hold the soil structure when uncharred woody and organic components around it have decomposed.
I hope this has provided some useful information and direction for your further reading. Whenever those question pop up, the membership of this site is usually all-too-happy to provide answers. Let us know how it goes, and good luck.