Is this illegal?

My husband was employed as a mechanic by an electrical company. He was laid off because lack of work (this was what he was told at the time of lay off) A few days prior he had a misunderstanding about a surge protector being taken from a clients home. His helper was cleaning up and accidentally took the surge protector from the home thinking it was from the work van. (It's normal for electricians to have these in their work vans) he recently became a professional truck driver and was applying to a company . He was turned down for the job because his previous employer said he was terminated for stealing the "extension cord". There was never any legal action taken against my husband for theft or anything. I am wondering if we have a case against the former employer for costing him this job by saying something that's not true.