Someone set up my fiancé now he's in jail

I'm so heartbroken and hurt. My fiancé is on parole and has been doing so well he did something stupid couple years ago stealing. But has turned his life around. He hired someone about his age later 20s to help him do this side job and he didn't really research this person very well. Turns out this guy has a past of overdosing and has mental issues now. Well this guy got upset with him because my fiancé had to keep stopping what he was doing to show him what to do when this guy explained he knew how to do the work. So the guy left and showed back up to the job site and tried to hurt him with people and told the police my fiancé put a gun to this guys head. My fiancé has no access to guns he's not even allowed to have a nerf gun while on parole. I also had his vehicle this day due to mine not starting so he had no way to leave to get one either. So bc he's on parole they arrested him. I found this guys Facebook he has gang related things and a picture of a gun on his page! They searched our vehicles and home found nothing. But he's still locked away until next week when they figure it out but I don't know what I can do I've contacted his parole agent she said she hasn't talked to him yet about this. But if they don't believe him he could do years. I'm so hurt and can't even explain how I feel! The officer and detective were very disrespectful towards me. I kept asking if they saw this weapon and if they have proof he did indeed put it to this guys head? They tell me no but there are people. The job site is in middle of country and nobody is around unless this guy brought people with him but they would lie to. And the home owner was on vacation. Sorry for my rant and my long story but this is so stressful and overwhelming and could affect the rest of our lives because of people like this!