Ancestry/Genealogy

Given that her last known address was NYC, a starting point would be the New York marriage licenses. See https://www.health.ny.gov/vital_records/genealogy.htm for NY's rules on obtaining a copy of a marriage license.

Check http://collegehistorygarden.blogspot.com/2014/12/new-york-colleges-that-have-closed.html for her closed college. If she went to college in another state, google that state and "colleges that have closed". It may lead you to where the records are currently kept.

You can also check the 1940 census to see if you can find her with her parents. That could give you some other leads.

Just keep in mind, his birth mother may not want to be found. Be sensitive to her right to privacy.