Well first let me say that I am glad that your wife and the old fellow were not hurt seriously. But I also need to say this.
Unfortunately, as we age our senses and reflexes deteriorate to a point where we should no longer be driving. I remember driving with my father when he was in his seventies and asking how come he stays so close to the white line (at the side of the road). His reply was "that's all I can see". He never knew, but I reported him to our licencing department, two days later he gets a letter in the mail to get a doctor's exam and a new road test. Well he failed the medical, and never took the road test; thank goodness!! He was quite upset about losing what he considered his independence, but after selling his Honda, he settled in quite easily into using taxis, and ended up having an account with them. Before he passed away he told me that he should have turned in his licence years before he had it taken away. I just hope I have the common sense to turn mine in before I have it taken away hurt some one because of my physical/mental deficiencies.