BTCapsule is an open-source program that can help timelock your bitcoin to a date of your choosing. You simply generate a P2SH address, add a date, the txid and vout number of your transaction, and the amount of BTC you sent to the address (minus miner fees).
This will create two folders with several files. You will get two separate paper wallets (sender_wallet.txt and receiver_wallet.txt).
The senders_wallet will contain a redeem script that can be used at any time to get your bitcoin back, just in case you ever change your mind. It also contains the master private key used to create the transactions.
The receiver_wallet will contain a timelocked redeem script that is not redeemable until the date you chose. They will also have their own private key to sweep the wallet.
Just copy the receiver_files folder to a flash drive and give it to your loved one. They will not get the bitcoin until you choose, and if you’re (hopefully) still alive when the timelock expires, just redeem from your sender_wallet and create a new transaction.
When you’re ready to redeem, just visit a blockchain explorer and broadcast the redeem script. Once it’s been confirmed, you can use BTCapsule’s Sweep Wallet feature.
Sweep Wallet
To sweep your wallet, make sure the wallet with your particular redeem script is in the same folder as BTCapsule. Run BTCapsule, enter an address and the amount of BTC you want to redeem (a little less than available if you want to pay miner fees), and it will create a new file called redeem.txt that can be broadcast on a block explorer.
You can download BTCapsule for Linux and learn more at:
https://btcapsule.com/
You can view the source code at:
https://github.com/BTCapsule/BTCapsule
I have also included a testnet version of the code, so if you have Python, feel free to test it out and see how it works.
UPDATE 11-15-2022
BTCapsule now creates two folders, sender_files and receiver_files, and puts the appropriate files in each folder. So now you just have to copy the receiver_files folder and paste it into a seperate USB flashdrive.
UPDATE 11-18-2022
BTCapsule (testnet) is now available for Linux! Try it out and let me know what you think.
When you download BTCapsule, you will have to right-click the file, select "Properties>Permissions" and check the box that says "Allow executing file as program" (Ubuntu). When you generate an address, Google "Bitcoin testnet faucet" and have coins sent to the generated P2SH address.
UPDATE 11-22-2022
BTCapsule (testnet) is now available for Windows!
Windows Defender may flag BTCapsule because it was made with PyInstaller. I do not have $500 for a signed-certificate right now. When you generate an address, Google "Bitcoin testnet faucet" and have coins sent to the generated P2SH address.