Maybe, you could entrust your security to your friend, for example, ask them to remind your family if you die, that you have a drawer where you store bitcoins, including all the security passwords to your account to make sure that they can access it. I think there's no reason for you to put up a puzzle for them to brute force your accounts just make it easy for them, the only problem you need is how you could make sure that you are the only person who can access your drawer, and to make sure it is secured. All you just need is a piece of paper, hide it in the safest place possible.