Yes, there are several things that he can do to help with this. Eating a low protein diet can protect the kidneys. Getting regular exercise like walking and drinking enough water is also helpful. Have him try walking more often for shorter distances if he is getting too tired after 1 kilometer. Eating a diet with lots of fresh fruits, vegetables and whole grains is healthy. Avoiding salt is good for the kidneys too. Salt is often very high in processed and canned foods so avoid them when possible. I know that you said you wanted suggestions other than tablets but there is one class of drugs called ACE inhibitors that is very protective of the kidneys in diabetic patients. Good luck and I hope he stays well for a long time.