Can anyone give me advice on this?

I'm not an attorney in that state and I don't know the specifics of the law or how strictly the laws are enforced by that jurisdiction. But I do know that the fact that your friend's husband voluntary took it upon himself to own up to his mistake is going to look very good to the prosecutor and the judge. Hopefully he will get a good MI attorney and the charges will be dismissed, or at worse, your friend's husband will get the minimum possible sentence/fine.