Welcome to the Forum!
Most people find that there was someone down the line that had diabetes in their family. My father had it and so do I, it's hereditary. There are many things that you can do to protect yourself, even if you think that you are susceptible to diabetes. The office job doesn't help, be sure to get your exercise. Loose weight if you need to. Watch for the signs, you could even check your blood sugar every once in a while.
Read through the first three threads in the Type 2 Section, when you get a chance, if you have not already done so. These threads will most-likely help you a lot, have your father read them as well. Self education is one of the keys to successful management of his diabetes, along with a healthy / sensible diet and exercise. Basically, diabetes requires a life-style change for the better. Good luck with his control and management.