I would like to know my dad suffered from renal kidney disease and I understand that food that is high in protein and potassium should be avoided.

What about fibre? like oatmeal?

I don't think there are many dietitians who view this site. You should try the sites listed below, they are all good reliable sites to learn more about kidney disease and dialysis.

http://www.kidneyschool.org/
http://rsnhope.com/
http://www.kidney.org/patients/
http://aakp.org/