Enjoyed many an afternoon watching Seaver pitch back when I was a kid and enjoyed baseball.
Sorry to heard of his condition but if one lives long enough, one can expect a diminishing state of mind. Our family have many generations of this disease.
Prayers for him and his family.
There are things you can do to mitigate it but there is no silver bullet. Lots of social interaction, reading/writing/studying and limiting “push” technology like TV. You don’t want the brain to atrophy.
Baseball is even better when you’re old.