Legal Question in Criminal Law in Michigan

This seems unusual to me. Usually such plea deals are structured that the defendant must testify truthfully against the co-defendant at trial. However, I suppose that if the defendant reneged, changed his mind, or refused that would constitute an anticipatory breach of that agreement. That does happen from time to time when a defendant has second thoughts or gets cold feet. I don't think I've heard of it happening quite the way you've described where the prosecutor determines he is violating the deal because she thinks he isn't telling the truth.

Is what he is telling her now different than what he was telling her before or contrary to what he told the police? It would make a little more sense in that regard. A lawyer has a duty not to put a witness on at trial if they believe they are going to not tell the truth. It would really only make sense to me if he is somehow changing his story.

Have you contacted his lawyer about this to get his thoughts or input? If he has already been sentenced in contemplation of fulfilling his plea agreement and the prosecutor believes he hasn't fulfilled that, they would have to motion the court for re-sentencing. Again, this seems unusual to me because normally his sentencing would not take place until after the trial so it could be determined whether or not he fulfilled the plea deal.

If you do not have confidence in his lawyer I would suggest getting him a new lawyer to get involved and see what is going on.