I've thought about this too. I keep a small binder with life insurance, brokerage, mortgage, other information in a safe place. I printed paper wallets of all crypto accounts, including my Steemit wallet and all the keys. My wife has no clue what to do with any of those things, but we have friends who we trust who are knowledgable, and I have instructions to immediately liquidate all crypto assets in the event of my death.
Tough to think about but absolutely necessary.