I am scanning the internets, as I am known to do, and I see a link to a
huge, zoomable image (yes, I just coined a term) of Yankee Stadium taken on July 4th of this year.
That was the game Dad was there for.
A quick email to Pops and I find out where he was and...

There he is out in left field.
This is probably a boring post to some, but I had fun with it.
UPDATE
Ally has called into question whether or not this guy is indeed Dad. To that I say, "Up yours, Ally."
In an email, Dad said that he himself found... himself...
left field ... it says "yankees.com" in lowercase on inner wall ( blue) if you start with the "n" go up at a 45 degree angle I'm about 12 rows back ... wearing dk blue yankee t-shirt with white NY on front and Blue Yankee hat ... I'm facing to the right in picture ... I'm 4th person in from left (beginning of row )Here is a slightly different view of the man in question:

So, Ally, are you calling our father a liar? Are you? You have some nerve.