Find adoption date of larry jacobsen cedar falls iowa 50613?

Question

he was adult about 65 yrs .last name was cornwell

Answer 1

He was adopted at the age of 65? Or 65 years ago? Or in 1965?    Was his adoptive name Jacobsen or Cornwell?

Answer 2

What you need to find out are adoption records from Iowa available to researchers.  Some states the records are not available to anyone, except for medical history.  Some states these records are only available to lawyers.  

It is also possible it was not a legal adoption.  There were children who were kidnapped even back then.

Check the records in Iowa and see what you find out.