Who says your father ticked the box. A lot depends where the card was taken out. For example if taken out whilst being canvassed and having the forms filled in by someone else then being presented for a signature and not having a copy at time of signing etc. Also would your father have been able to claim should the need have arisen? If he was self employed or retired there is no way PPI was suitable for him.
Will your friend be prepared to put in writing what has happened, in particular the threat to tell your employer - and also what was discussed with her. Do you know if the Agent was wearing a camera and if it was running. Was the camera running when he spoke with you.
when it drops below 500 you can transfer