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 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 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.

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.