There is no wallet that your family and heir can just simply access if you are no longer there, you have to give them your seed phrase, or prepare an inheritance strategy that works for you.
Not your keys, not your coins.
This has been replaced by hardware wallets, so no need to use it. Since you are looking for long term storage, which should be a cold storage wallet, then a hardware wallet is what you need, dyor before buying a hardware wallet and buy only directly from the manufacturer.