That £700 from 1965 is now worth £13,600. He should pay it back if he can, even if any legal obligation has expired. But not the first class return ticket, that seems to have been freely given.
Perhaps it was an unjust contract in the first place that trapped a 19 year old thousands of miles away from home and with an unpayable debt over their heads.
yeah what if that was an etherum or cardano smart contract?