Old Age and Driving

I was in a local Starbucks yesterday. Inside was a very nice old guy somewhere between the age of 80-85. He was walking really slowly with his coffee as he also had a cane. I saw him leave. I figured someone in the parking lot had given him a ride or he lived nearby. He was walking incredibly slow carrying his coffee. I got out into the parking lot and watched him get into his vehicle (which took no lie about 5 minutes). I was shocked. There is no way this old guy has the reflexes to operate a motor vehicle. Now comes the dilemma. Should I report this guy or not?Well I took the license plate number down. Will anybody do anything if I do report it? I realize that a car still gives this old guy his independence but the safety of others has to be considered too.