Most diabetics do not require insulin.
As far as an FAA medical, you can get ALL classses of certificate on oral medications. The FAA just wants documentation that you are well controlled and have no adverse effects from the medications and no damage from the diabetes. See the link here
http://www.faa.gov/about/office_org/.../diabetes_med/
Third Class medicals can be issued to those on insulin but the rules are really tight and there are a whole bunch of hoops you have to jump through when you fly. This is the link for insulin controlled diabetes:
http://www.faa.gov/about/office_org/...betes_insulin/
It sounds liek your family has type 2 diabetes which tends to be inherited. The tnihgs you can do are exercise, keep your weight down to lean body mass, eat a well balkanced diet low in fat and carbohydrates. If you notice, most type 2 diabetics are middle aged, overweight, don't exercise and eat poorly.