There is nothing in the law which strictly prohibits a former employer from telling future employers about an issue they had with your husband, however, if no conviction was recorded your husband can state that was not convicted of anything. If the former employer is exaggerating what happened then your husband likely has good grounds for defamation action and your husband could in priniciple sue the former employer for damages, which would include a claim for any lost employment opportunities and any overall financial losses which may have resulted. Moreover, if he has made any of his false or exaggerated allegations in writing to former employers (i.e. written them a letter) then the fact such behaviour appears malicious could amount to a crime:
It would also be arguable that such behaviour on the part of a former employer may amount to stalking under the Crimes Act:
particularly if you put the employer on notice that your husband may become depressed as a result of the former employer's behavior.
I would suggest a strongly worded warning from a solicitor advising of the above matters may suffice to dissuade this former employer from persisting in such action.
I trust the above assists.
Good luck and PLEASE RATE MY ANSWER.