If your mum has had problems with urine infections and kidney disease, peanut butter is not a good choice because it contains purines which can cause
kidney problems
and to the formation of
kidney stones.
Any type of food in small quantities is fine, but not highly refined and sugary foods. Use brown bread instead of white. If your mum will only eat white bread, then give her a small piece. Vegetables are a good choice, just go easy or avoid peas and sweet corn.