This can actually be a little bit tricky in the US, since unsecured lines of credit are sort of a disappearing product at many banks. (They're strictly inferior to the bank as opposed to having you do a CC cash advance and their risk profile is off the charts because anybody whose need is "I can't get a credit card but..." when American banks hand them out like candy on Halloween is not generally a great credit risk.)
You can find them (particularly at credit unions) but they're not, to my understanding, as common in the US as in commonwealth countries.
I have $42,000 in credit with a major bank on credit cards, and just received an $8.5k 0% balance transfer from another (they just put the money in my account). I've earned basically nothing in the last 6 years (been a student). Unsecured credit is out there, it's just about establishing a credit history, which I've been doing since I was 18.
The flip side of this is that credit cards are handed out like candy to basically anyone with a decent credit history (and several people without). I would go the CC route; if it's just for a month until the paycheck hits you might even make it under the grace period, and even if you don't, if you pay in full over the next month or two the interest is negligible.
He'll likely find both no grace period and a fee for cash advances but, either way, it will probably cost less than $250 to borrow $2k for 6 weeks. (I am broadly supportive of your advice to smooth out temporary cash flow issues with financial services. That is what banks are for. Obviously, one does not want to make a habit of this, as cash advances are very expensive ways to access one's credit.)
You can find them (particularly at credit unions) but they're not, to my understanding, as common in the US as in commonwealth countries.