Do I have to pay back the vacation time I used now that I'm quitting my job?

My husband is leaving his job of 5 years to go to another place closer to home. He took vacation in April and didn't even apply or get hired in to this new job until this last week. Now his current employer is asking him to repay the vacation time he used up in April (in other words, he won't be getting a last check for the two weeks notice he gave them. Essentially working for free these two weeks.) Is this legal? This happened to me when I worked at Wells Fargo years ago, but I had to sign a contract saying that I could borrow against my unearned vacation time if I needed to. I ended up leaving within a few months of being hired, but had used up some of my vacation time and had to pay it back. My husband works in a factory, he says they never signed a contract like such. How do we find out if 1. This is just a way of them being nasty and 2. If he signed such a contract without knowledge (not paying attention). Thank you!