Wallets and most exchanges to my knowledge don’t have the concept of beneficiaries. If I got hit by a bus today, the contents of my wallet(s) are unrecoverable.
There are a class of algorithms such as Shamir’s Secret Sharing that makes this more tenable. For those not familiar, it breaks apart a secret into N number of pieces such that it requires k pieces to reconstruct the original secret.
Would you entrust friends and family with this information? Are there better ways to do this like simply leaving a paper copy with instructions in a bank vault?