Your father must avoid sugars, fruit juices, cakes and pastries. Among fruits he should avoid mango, litchi, cheeku, grapes, custard apple, banana and dates. His diet should be low on cholesterol meaning he must avoid saturated fats (fats that are solid at room temperature derived from animal sources). He should avoid buffalo milk. A balanced diet for him should include-
Morning - One cup green tea with two diabetic/cream cracker biscuits.
Mid Morning - Any fruit other than what I mentioned he should avoid.
Lunch - Rice-60g raw weight or three small chapattis, vegetable (avoid potato and coconut)plenty cooked with minimum oil (combination of equal quantities of soyabean and sunflower), dal (if his uric acid is not high) or non-veg-chicken/fish (1-2 pieces).
Evening - Tea with biscuits/ 1 toast with mint coriander chutney/sprouted dal (check uric acid levels please).
Pre-dinner - 1 bowl of soup (hot or cold) with mixed vegetables.
Dinner - Same as lunch, prefer vegetables, include salads - 100g per day and fruits- 75g per day.
In case of your mother, the same norms should be followed as your father. She could even have the same diet, but quantity and quality wise there should be no compromise. Ensure your mother does not have foods containing preservatives, she should have normal salt in her food.