The answer
They may need a passphrase, multisig descriptors or cosigner details, asset and chain inventory, instructions and lawful estate authority.
What to do next
Create a secure estate inventory without placing every recovery component in one accessible location.
Trezor hardware wallets
Potential cold-storage product; not a substitute for safe backup procedures. Availability, supported assets and local eligibility must be checked before signing up or buying.
Visit Trezor hardware wallets ↗Official provider link · Compare suitability and availability before choosing.