My brother is 29, has been having pain in his right lower back under his rib cage for about a year now, and has brown urine with specs of visible blood in it. He went to the docs, they gave him an ultrasound on his kidneys, found no kidney stones. They also didn’t find any infection. They said he has high amounts of protein in his urine. Are there any conditions he might have and what foods/drinks should he avaid?