This is a topic that came up a lot in 2018 when the legislation around data protection was updated. In my data protection policy, my lawful basis for storing records is that it is a legal obligation: “The Limitation Act 1980 requires information to be held as proof of an activity against the eventuality of a claim. Consequently, archiving notes after speech and language intervention has ended or a complaint has been resolved is a legal obligation.” (NB It’s this act that stipulates the period of time for which we have to keep our records, which is because of the possibility of litigation.)
Given this, I would say that when you are no longer around to be litigated against, the reason for storing the information is no longer valid and there is no lawful basis for processing data, which includes storage. Therefore they should be destroyed as soon as possible and securely to ensure confidentiality is maintained.