The main thing to avoid when cooking for diabetics/prediabetics is processed grains. Sourdough breads metabolize better than plain white breads. Avoid pasta and white rice. Focus on lean meats and veggies.
Pot Roast and roasted root vegetables is a great 'man' meal and very easy on the blood sugar. Use the drippings to make the gravy.
Chilli is another healthy meal if made from scratch, and it's quick to throw together. Just throw some chopped onion, bell pepper, fire roasted diced tomatoes, and 2 small cans of green chillies in a pot with your choice of browned meat (chicken, lean ground beef, or ground turkey) and a couple cans of beans (any kind). Season with salt, pepper, cumin, and chilli pepper to tase. Bring to a simmer for about 20 minutes and serve.
If he's not a fan of steamed veggies, try roasting them instead.
For breakfast, english muffins and eggs.