As you have noted, you did not locate an authorization in the file to release the content of of the file.
There may be legal mechanisms that interested parties can utilize to obtain access to the file, but in the absence of a legal requirement to provide the information, the professional standards would otherwise continue to apply, and you would maintain confidentiality, as you would for a living client.
Additionally, under the Personal Health Information Act, an individual may be designated as a substitute decision maker who could access a record. If this were the case for his wife, then this designation may extend beyond death. I’m sorry but NSRP cannot provide legal advice and cannot say for certain that if his wife was designated as a substitute decision maker that it would continue to extend to this point in time. We can only state that this may apply and you would need to obtain legal advice in the event that his wife raises this matter or would like to investigate such a question at this time.