There should be documents filed with the Court where the parties lived back 25 years ago that would support the annulment. I would not be in favor of proceeding with a marriage unless you have proof that the prior marriage was dissolved either by annulment or by divorce. You don't want to commit bigamy.
The information provided in this answer does not create an attorney-client relationship and is not considered to be legal advice.
An annulment has to involve a court proceeding and there has to be paperwork. Where was his wife living when she had the case annulled? The courthouse in that county is the best bet to find the documents.
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