Well this issue needs to be discussed by every bitcoin user bit no-one thinks about it. As giving your seed phrase might be risky but what if you put it on a safe place and mention it in your will which much be disclosed after your death.
Yeah, every man who has enough wealth to be given to its beneficiary can just make its will, including the wallet name, passwords, seeds, etc. with the power of attorney.
But if you don't trust such way, you can just make your family members knows about your cryptocurrency thing, let them know where you pull all your holdings and how to access it.