I am so sorry for your loss.  If your Father's wife was the named beneficiary on the insurance policy then that money is said to pass "outside the estate" and would go to her directly.  Generally speaking, that means that she does not have to share it with anyone.  Emails are not always accepted as "evidence" of an agreement or a Will.  Please take what you have to an experienced estate attorney to review.  But I would not get your hopes up.  Good luck.