There are many ways if he rely on trusted people or 3rd party which already mentioned by others.

Otherwise, the closest things that i could think is using P2SH transaction/bitcoin script where the receiver only can claim the Bitcoin after n days/blocks. To prevent claim abuse while he's still alive, he could remake the script with different timelock before current timelock is "expired".
The rough code should look like this (i'm still learning bitcoin script, so most likely it's inaccurate) :