Hired, then fired on same day?

My husband went through an employment agency for a job. He was set up an interview with a local company that specializes in his field of work. He was told at the end of the interview that his resume was impressive due to 25 years experience and that he had the job and could start next week. They also said he would be scheduled to take a drug screen tomorrow and would be in touch with him. He received a call from the owner (not the person that interviewed him) and was told that they would not be able to employ him because the employment agency required payment from them since he was hired. Then the employment agency called my husband and said that since he was under contract with them, he could not legally apply at the company on his own until 6 mos. from now. The employer has scheduled another person to interview tomorrow morning for the position that was supposed to be his. We know this because it happens to be a friend of ours that worked with my husband that had called them today inquiring on any open positions. Imagine our shock when we found out it was the same company he was interviewing with. My husband was told he could sue them for breech of contract but he never signed anything to start employment. He was only told verbally that he had gotten the job. He had not even done the drug screen yet. I was always under the impression that you aren't legally hired until after you fill out the tax forms. Personally, I think when the owner realized someone was coming in that was NOT through an agency that requires payment, he decided to back out of hiring my husband. You can't tell me this guy didn't KNOW he had to pay an agency if they hired one of their applicants.

Question 1: is there anything my husband can do legally?

Question 2: Now, I understand WHY the agency doesn't want him to go apply on his own but can they stop him legally? Please advise!