My recommendation is for this person to return to Wisconsin, turn themselves in to their probation officer, and address this with the Court as soon as possible. I'll explain why.
Right now they're in violation of their probation, and as such there will be a bench warrant out for their arrest. What that means is that if this person is stopped by police at any time, in any state, for any reason (even for a missing tail light or any other minor traffic infraction) once their ID is run by police officers, the warrant will show up and they'll be taken into custody.
The potential penalty for the violation of probation is exposure to the maximum penalty for the original crime they were charged with. Since this was a class A misdemeanor, the maximum possible penalty is a jail sentence of up to 9 months. The Judge can however do a variety of things besides assign the maximum penalty-- for example, he can reinstate probation, give a short jail sentence followed by probation, or followed by no probation, a fine, rehabilitative classes, or any combination of the above.
The sooner it's addressed with the court, the better, and turning himself in rather than having officers pick him up and extradite him back to Wisconsin, will look better to the Judge and be more favorable to his case.
I hope that helps! Please let me know if you have any other questions. Also, please take a moment to rate me using the stars as this is the only way experts are compensated for our time here on 'just answer'. It doesn't cost you anything to rate me, and we can still continue our conversation for free after. Thanks!