Is his nose congested to the point that he can't breath when nursing? If so, sitting in a steamy bath and squirting saline or even bm into the nose and trying to suction out the mucus may help. As much as they hate it this is the only thing that has helped mine when they are sick like that. Also, if you haven't tried Tylenol or Motrin yet they might help. I don't like to give unnecessary meds but if he isn't eating it might be worth a try.