If JP was involved with drugs I don't think the wife would admit it knowledge of it or she would be wise not to.
I have a friend of a friend here in FL who spent a year in state prison because the state prosecuted her for knowledge of his husbands drug sales. She never admitted knowing but the state felt that had to know and she was found guilty at trial. She was from a rather nice well known family and their only child have to go live with relatives.
Of course admitting any illegal activity he might be involved with might help with the investigation but I think it is too late to save him.
I'm sorry, I don't know you or your friend who's friend supposedly spent time in prison simply for having "knowledge" of [her?] husband's drug sales BUT I think you were decieved. More than likely, they found drugs in "their" home. It's her 'bad' for not knowing. If she knew something & was willing to help LE in some way, she may not have gone to prison.