Have him take a look at the Primal Blueprint from http://www.marksdailyapple.com/primal-blueprint-101/ Lots of science based information.
Lots of success stories of people dealing with type 2 diabetes, some even putting it into all but remission.
Obviously, your brother should speak to his doctor before doing any major changes but my advice:
* Get rid of all grain based foods, breads, pastas etc. * Get rid of all vegetable oils/seed oils (High in omega 3) * Limit fruit intake * Limit carbohydrate intake (fruit drinks, soft drinks, potatoes, etc.) * Eat plenty of healthy fats * Remove all/most processed foods, cook home meals as much as possible. * Do lots of steady state cardio (i.e go for long walks) * Try lift some heavy things (2-3 times a week in the gym just lifting some weight)