Well, not really. If you e-sign a document, it's not like there's no traceable provenance to the signature to establish your identity. To what email were the documents delivered? What computer/device were they signed from? At what location were they signed?
Sure, all of those things can be "faked", but they really only matter if the signature is disputed. In this case, that's happened, and it will be quite easy to prove he didn't sign the documents.
>This fake signature is just an acknowledgement that signatures are useless
This is a bit of a reach. Signatures are not meant to be a secure identity measure. If the story is as explained in the Tweet, it's fraud, and that fraud can be proven thanks to what was or was not actually signed. The story doens't end with the insurance company pointing to the signature and saying, "Look, there it is".