I would ask your adjuster what the company would like him to do, and do that. It’s their duty to defend and indemnify him so they should be deciding how that happens.

The letter stated that they cannot offer advice on whether he should consent to the disclosure, and to seek counsel at his own expense.

I don't think you are going to get the answer you want one way or the other from the forum.

Your father will have to weigh the difference between saying yes or no.

That might be what you can ask the adjuster. What if I say no, what could happen? or What if I say yes, what then? Or even...out of 100 clients, do a majority agree or not and why? They may or may not answer but it might help you decide.

This will eventually your father's call.