Yes, but that's not the only problems that can bring on extreme thirst and frequent urination.
Realize that some diabetes is on how the body functions, not what you put in it. Some diabetes you do get from a bad diet though, but not all.
It is extremely hot most places and he just may not be getting the hydration he needs during the day. If he is drinkign any kind of soda (even without sugar) they are full of sodium which makes a person even more depleted from the life giving water that is needed to run our bodies.
When you get up with him in the morning, make sure he drinks a good 10 to 12 ounce water with his breakfast. Bring him in every hour and make sure he gets another 10 to 12 oz of water if he's outside and playing. Lunch, make sure he drinks even more water, another 12 to 18 oz of water. Make sure there's a couple of times during the afternoon he gets water intake. Same wiht the evening. See if it doesn't help him need water in the night. It's when his mind is shut down and his body finally gets to rule and the signal is... hey.. i haven't had enough water to run our body properly!
I would be less worried and instead find ways of getting more water in him during the day when his body needs it most. Kids don't like to slow down for water breaks. Plus, kids with friend would rather have good stuff like energy drinks, sugary drinks or fruit drinks. None of which give your body what it really needs. Tea and koolaids do not feed your water need either. Ever drank a large tea to only need a second glass right away? Didn't quench the thirs like plain ole water will.
Getting him cool ways to carry water might help him drink it a bit more. Something that will help keep it cool. Who likes hot water? eeww. At night for a treat give him a popcicle or kool aid instead of anything salty. yes, i just said they don't quench your thirs properly, but it will help little bits. He gets a treat and something he wants at same time.