OK, so now I have what appear to be 2 good and uncomplicated options to solve this problem (thanks again everyone!).
1) I have OmegaStarScream (forum staff) telling me to download ELECTRUM (on my Mac, which I already did), then import my BTC private key into Electrum and then send it from Electrum to my father's Coinbase BTC receive address. That sounds quick and easy, just what I was hoping!
2) Then I have magick (forum newbie) telling me to download BlueWallet onto my dad's iPhone (which I thought we had already tried but I will have to check again, maybe not) and then import the paper wallet by simply choosing that (Import Wallet) option and entering the 52 character private key, which then allows access to the BTC, which I can then send to my dad's Coinbase BTC receive address. Sounds equally quick and easy as the first option.
(OmegaStarScream and magick do either of you have anything to share about the others' recommendation?)
So which is better?
Is there a "better" or is it just a matter of preference and comfortability?
Is 1 of these 2 seemingly great options clearly a preferable choice in any way?
And, BTW, nothing in any of this advice have I seen "go offline" or "disconnect from the internet" type instruction. It appears that these days you can just type a private key into Electrum on your web-connected Mac or BlueWallet on your 5G connected iPhone and the BTC will just show up without hassle or fear of loss/theft. Is that really true? That's what it sounds like.
Thanks again.
Both options are valid, as long as the apps are from a legitimate source and your devices are not exposed to malware. However, the safest options are:
1-Import it into a hardware wallet.
2-Import the private key into Electrum on a device without internet (air-gapped), and the public key into Electrum on a device with internet.
In the latter case, you create and export your transaction from electrum (with internet) to a file, transfer it to a USB, sign it in Electrum (without internet, this device should never be connected to the internet, so that the private key is safe) and then export the signed transaction back to the device with internet to transmit it.