I would write him an official notice with a copy of the employee handbook where it states that all employees earn vacation time after they have been there a year. They earn a day of vacation for a certain number of days worked.
This way he can see, in writing, what his expectations are. So many people are seeing a crappy workforce coming out of colleges these days. Even younger too.
I can't imagine this guy expecting to work at a job for 6 months and getting to announce he's taking a weeks vacation and he expects to be paid for it. Good riddance.
I've never worked anywhere that "I" didn't earn my vacation time and I couldn't use any of it until after I'd been there a year.
I don't think your husband should pay him any vacation time until he's been there over a year.
I have a friend that opened a Greek place and he's had the worst time getting employees. He had about 25 people, mostly high school kids, come in and fill out applications. Nearly every single one put minimum wage expected as $15 per hour. He tossed each and every one of those in the trash.
He had a couple come back in. He told them he didn't have an application in their name. They chatted a bit because he was willing to give them a try because he was having a hard time getting anyone to work.
They told him they thought minimum wage was $15 per hour and that they deserved that much. He told them they were deluded and that minimum wage was $7.25 an hour. They laughed at him and told him no one would work for that much.
Guess they don't know where money comes from, that bills have to be paid, and that they are going to make a lot less than that while they're on un-employment while waiting on those high paying jobs.