The amex Blue Cash Everyday would probably be a very good fit. No annual fee, easy to use categories for anyone (3% groceries, 2% gas, 1% other). Has the good ol money saving amex offers tab. Usually has 0% apr for 15 months. Often a $150 sign up bonus (so the person will be getting 1% off and then $150, essentially!). After being comfortable learning to use a credit card, they could upgrade to the BCP a year later.
The amex cash magnet is another good choice--usually very similar sign up terms and is a 1.5% cash back on all card.
Since no credit cards, but having other lines of credit over the years, hard to say if they'll give the instant usage number for sure.
I would call in to apply over the phone and try asking if it'll be available, and offer to send in personal verification via email if need be.
The apple card is an option...but the spending categories are pretty bad, in my opinion.
If unable to get a card to use INSTANTLY, you still have a simple instant option.
Just take out one of those instant approval/next day deposit loans. Yea, the interest rate might be 25% or something absurd. But that doesn't matter. The loan only needs to be open for a couple days. Apply for the right credit card with a sign up bonus and 0% apr intro.
Just make sure you can pay off the loan early without a crazy early pay off fee. And that the lender accepts credit card payments (and of your new credit card type (not everyone will accept amex)). If they don't accept credit cards, you could look to open a Visa with 0% and pay via plastiq (note: I'm not super familiar with plastiq. Confirm if you'll be able to have plastiq process this type of payment) for a small 2.5% fee.
So yea...next day money loan that accepts credit card payments & has no early pay off fees (or nearly none). Ignore interest rate.
Tip: applying for the credit card & loan same day is important. Don't wait 3 weeks after the loan. You DON'T want to have that loan getting a chance to show up on credit reports before applying for a card.