Christopher Plummer was 71 in A Beautiful Mind when he played the character 'Dr. Rosen'.
That was over 22 years ago in 2001.
In 2021 he died aged 91, starring in 176 films in his career, 64 of those after A Beautiful Mind was first released. If he were alive today he would be 94.
In A Beautiful Mind, I think Christopher Plummer looks: