Hi Amy,
Leah's instincts are right on this...going to the DOL site on Wage and Hour compliance is a great place to find some potentially helpful info on your husband's situation.
(
http://www.dol.gov/compliance/guide/minwage.htm)
Like Leah said, THE crucial issue here is whether or not your husband meets "exempt" status--not according to the employer's standard but according to the FLSA's definition. You wouldn't believe how many employers have their employees classified the wrong way (some intentionally, some by accident), especially in the construction industry. There's a very helpful Overtime Security Advisor on the DOL site that breaks down the various threshold requirements for each exempt status.
(
http://www.dol.gov/elaws/esa/flsa/overtime/menu.htm)
Likewise, here's a link to Fact Sheet #17A, which is a short-and-to-the-point document on defining exemptions under the FLSA...
(http://www.dol.gov/esa/whd/regs/compliance/fairpay/fs17a_overview.pdf)
And finally, as your husband asseses his options, I'll borrow a quote from the DOL site on FLSA Compliance:
"It is a violation of the Act to fire or in any other manner discriminate against an employee for filing a complaint or for participating in a legal proceeding under the Act. "
I hope this helps. I work with employers on auditing their compliance practices with FLSA and the DOL, so I see these situations all the time. Feel free to contact me if you have any questions. Good luck.
Jared Bostrom
Burnette Insurance Agency
Risk Management
jared@burnetteins.com 
