Tell him that you have been trying to learn more about these harmful effects and that you can't find any actual papers or studies on the ill effects of high-protein, high-fat intake among people that are severely limiting their carbs. That you can find lots of information on ill effects in people that are eating normal or near normal carb level, but that you don't see why the effects would be the same. Ask him to point you to specific papers that address that specific question - the ill effects of high-protein and high carb in people that are also severely restricting their carbohydrate intake.

As for a directory of LC-friendly doctors. I don't know. I would imagine that there are lists someplace.