electrolytes, especially sodium, are very important to fat digestion

i have had chronic low electrolyte levels and hypokalemia for a few years now, only just figured it out, and too much fat in my food normally causes diarrhea... but if i have added enough salt and i'm hydrated, instead i'm now experiencing quite elevated body temperature and some signs of ketosis, meaning i'm making energy from it

i'd also suggest examining the effect of the diet he's eating in relation to intestinal motility, if it's too high, and something in the food is causing the intestines to move too fast it will cause dehydration and loss of electrolytes, and that will in turn cause less effective absorption of fats, and a general decline in metabolic function altogether