Cookbook needed - heart disease AND diabetes

Does he like to eat herbs? You can make a lot of bland things interesting with them, maybe a low fat yoghurt and herb dressing for the chicken? also because if the salt being cut out a few grinds of black pepper livens things up. For desserts try sugar free jellies with fruit in.
What about rice, you can cook rice with saffron or turmeric in the water. BBC's website has paprika chicken which you cook all in one pot and is lovely. if you use a little bit of olive oil you should be ok with that one.
Pasta can be boiled and served with a fresh tomato sauce, cooked tomatoes are good for the heart, if you make the sauce yourself you are in control of the fat, sugar and salt content.
Its worth looking at sites like the BBc's food and others and looking under the low fat secton and low sugar section and seeing if they overlap.

Good Housekeeping's Eat Well, Stay Well has over 300 recipes suitable low fat, low salt, low sugar etc diets. I got it a few years ago from the Book People and have had loads of use from it!

if hes just been diagnosed he should have an appointment with a dietician being arranged for him and he will be given the british heart foundation handbook which outlines some recipes and ideas on how to adapt his eating style.