Niether of my children, both w/ CAH salt losting, never or dont drink very much. About 16-20oz. per day of formula once on baby food. I do put formula in cereal and my 6 mos old eats baby food too. I went to the Dr. yesterday w/ the same worry about him not drinking enough ( he is 6 mos.) The Dr. said not to worry, all kids drink different amounts. But I have had to adjust sodium because he is not drinking as much formula. Are you giving sodium? I know it is hard not to worry, just try and stay on top of things without driving yourself crazy. Have they check his other levels, is he getting enough cortisone? That can affect appetite? Good luck.