SecondAttempt
Thinks s/he gets paid by the post
If they require DL info, do they at least have a secure message service. Putting it in an email seems risky but I think I have provided DL # on various web forms for established, well known recipients.
I would point out that in most cases it is illegal to copy a DL, passport, or other government ID. So at least inquiring why they are asking you to do something illegal might be worthwhile. I think this is partly why US financial institutions have developed alternative idendity verification methods.
I'd also point out that I refinanced my mortgage about a year ago. My mortgage broker had to LOOK at my ID and fill out an affidavit that she had verified it but did NOT copy it, specifically telling me that it was illegal and it would taint the document review process.