my husband works for a company that works about 60 or 70 hrs a week. They only get paid regular time even for all that overtime, is this legal?

It depends on whether the employer is subject to the Fair Labor Standards Act and, if it is, whether the employee is exempt or nonexempt.

What kind of company is it, how big is it, and what exactly are your husbands' job duties?

It is construction company, my husband is the supervisor and has been for the last 10 years, owner used to pay overtime then all the sudden stoped, they get paid hourly, weekly, there is 5 other employees..taxes and everything is taken out of check...my husband works all week and weekends, if someone was to report company to labor board,is everything confidential?

Check the Executive and Administrative exemption criteria here:
http://www.dol.gov/esa/regs/compliance/whd/fairpay/fs17a_overview.htm

If he doesn't meet the criteria to be exempt, then he must be paid overtime. The state can't order the employer to pay him if they don't know who he is and, frankly, they probably have way too many claims from people who have identified themselves to be chasing employers of employees who don't.

Having said that, however, if he does file a claim for unpaid overtime, and he is fired for it, he would have a wrongful termination case under Texas' whistleblower's protection laws.