Your husband must read the question very carefully. If the question is has he ever been convicted or adjudicated guilty then the answer is no. If the question is has he ever pled guilty then it depends on how he pled: if he pled no contest then the answer is no. Of course, if the question is has has he ever pled no contest or guilty then the answer is yes. If the question is has he ever been sentenced then the answer is yes. If the question is has he ever been arrested or charged with an offense then the answer is yes.
His "record" will still show the charge and it will show he had an adjudication withheld. If he is otherwise eligible and his sentence is over he should hire an attorney to file a petition to have his case sealed.
This is not to be considered legal advice nor does an attorney-client relationship exist.