It is known that viruses can trigger diabetes. However, there has to be an underlying tendency to develop diabetes. Several viruses have been implicated in the past, but it is likely that there are several viruses that can trigger diabetes, probably by affecting the immune system into recognising islet cell as foreign. However, viruses are only half the story, and a genetic tendency generally exists also.
JS
Additional comments from Patricia Larsen:
You did not mention what the name of the syndrome your brother has. This would give me a better idea of what is actually going on.
There are a couple of possibilities your brother can try. The first being a bike called a Schwinn Airdyne. The arms and the legs on this bike both move, which allows the individual to just use their arms, or just their legs, and in the case of your brother, both arms and one leg. Your family has the option of purchasing, renting or finding a facility that has one you can use. You may find one in a fitness center. Another option that I tell people about is an upper body ergometer or an arm-cycle ergometer. This option is good for people who have limited use of their legs. Basically, it is a device that works much the same way as a stationary bicycle, except that you use your arms to pedal instead of your legs. There are both freestanding and tabletop models.
One other aspect of health that is important for your brother to maintain is his muscle mass. Weight training would be of benefit to your brother especially due to the fact he will be immobile for a period of time. Lastly, in either case make sure that he always checks his blood glucose before, during and after the exercise bout, including weight training sessions.
PL