Since the ransom wasn't made known then we should just keep crypto related thing out of this. We either don't know the net worth of this crypto fortunist which the reason for his kidnap maybe based on how notable wealthy personality in his environment afterall before crypto existed kidnapping has been taking place and other values a.rw being demanded for the ransom.
Except the crypto person has been made known in the society and due to his cautiousness not to befall physical victim such as to the kidnappers, member of his family maybe on the target.
But still, I find this fathers kidnapping experience hard to be related with crypto based on the details of the information.
That of David Ballad the co-founder of French crypto-wallet firm Ledger own was obvious that he as an affiliate of crypto was the actual victim at this time of being kidnapped and ransome was involved with crypto.