First off, even if I were the richest man in the world, I would not buy a 75k ring for an engagement or any woman unless we've been married a while.
Secondly, he must be clueless to not know she would refuse his proposal. If you are in sync with your woman, you know what the answer will be.
Thirdly, why would this lady dare keep that ring that didn't belong to her? And the father, who the heck is he? He should go fall off a cliff for possibly trying to get in his "grown" daughters business, and then trying to off with the ring.
Losers from both parties.