One quick thing here : If he has the ability to bring water to a boil, than, conceivably, he could use a "stove top autoclave". Sure, they aren't anywhere near as nice as a medical grade quality, but at least would have the steam/pressure to give his instruments a more through cleaning.
Just an observation/tip.
That said, it would only be 1 of the myriad of health issues that need addressed that'd be taken care of.