Take the emotion of the fact that the poor guy died out of things:
If a deal was agreed in principle for a player to move, but the final contract hadn't been signed, and on the way to the office to sign it the player falls down the stairs and suffers a career-ending injury, is the buying club still liable to pay the fee?
Assuming of course the "final contract" definitely hasn't been signed and isn't a smokescreen for Cardiff to avoid paying.