Hard to tell, The stages of kidney disease are i, ii, iii, iv, and v. Failure is a vague word if he is on dialysis is different than if he is not. Diet recommendation will vary according to stage of disease.
See my diet sheet. Http://www. Schwartzdiabetesdoc. Com/newsletters/_3_diet_sheet. Doc basically avoid simple sugars and patient will know if they have other restrictions- high potassium foods, high protein foods.