So for those who don't follow soccer, Emiliano Sala is a soccer player who died tragically on a plane. He is flying as he was transferred from Nantes FC to Cardiff City for 15M pounds.
If you wish to read more, you can google his name, or read this: https://en.wikipedia.org/wiki/Emiliano_Sala
My forum is about the dispute that the two clubs having in regards of the transfer fees.
Should Cardiff still pay Nantes for the player that never arrive?
This issue is currently being investigated by FIFA.
Without removing any respect to the player, I couldn't help draw a comparison: A seller ships a high value item to a buyer privately. Unfortunately the item has gone missing. Should the seller still get paid the full amount of the item, or should the buyer get a refund? Or should they discuss a way to share the lost halfway?
In regard to your scenario, there are agreed terms which include when the item changes ownership from the seller to the buyer. In addition, insurance is usually in place aligned with that point of changing ownership.
Without knowing anything about the agreements that football clubs sign when buying / selling players, it is impossible to comment on the initial scenario.