I think this is a really important thing to consider. I would hope that a Freetrade account would be uncovered and dealt with as a part of probate, but having a list of investment accounts (not necessarily a stack of account numbers that could pose a security risk) that is known by a close family member is really important.
At the grand old age of 29, I’m not planning on popping my clogs any time soon, but I’ve made sure there are records so that my wife knows where our investments/pensions/savings are in case the worst was to happen. An even better option would be for her to be actively involved in our personal finances, but she’s not all that keen (yet!).
Making mention in your will would also be a smart move I reckon. Talking of which, I need to update mine!