Before my husband was diagnosed / began to take control of his condition, he didn't stop eating and was quite aggressive in his demands for food. I think this happens because, as a type 2 eats more carbohydrates (sugars, bread, pasta, cereals, rice, potatoes), they produce more insulin, which their bodies can't process, but which sends out hunger messages, causing them to eat more food, and so it goes on. May not be quite right on the details, but there is some sort of vicious circle operating. This cycle has to be broken and the way many on this forum control type 2 diabetes is by severely restricting sugars and carbohydrates. It's tough at first, but many have seen great benefits. As far as I know, heat does not affect type 2.
You say you are sharing a house with friends, which implies you might all be in your early 20's, though I do appreciate the need to house share, especially in London, goes on for a few years longer than it did when I was that age. I just raise this because it is fairly unusual, but by no means unknown, for someone of that age to be type 2, which is traditionally associated with middle age and older. Anything I have said above refers to type 2, not type one, which is dealt with differently and has its own set of problems.
Try and get your friend to look at this site and forum, there's lots of useful information and he probably isn't happy with himself either.
Sally