1) Were the words in understandable English, or were they incomprehensible letters and words?
2) What is the date that file was created/modified?
3) What is the file extension? Is it txt or did you open the file using Notepad and it worked for you?
4) Are there any additional files, names of wallets, or any additional information?
I think you opened an encrypted/encoded file, so your answers to these questions may help us a little.
If the words are in English, make sure they are in this list
https://github.com/bitcoin/bips/blob/master/bip-0039/bip-0039-wordlists.md1. These are not words it is @77911F37HC........@
2. File created in 2012 and last modified in 2013
3. It is a .txt file
4. There is no other information there. Except if this is somehow password-encrypted, his wife might know the password as he always used the same password for everything It is kids' names with dates.
At first, I thought is was AES encryption, but my best guess it would require IV and 32b keys, but there is no key in a text file. I really doubt that he could do some advanced encryption as he was not a computer geek.