I think Flynn was treated poorly. I do not think he has anything on Trump and I do not think any association will even touch trump. That said I do think that Flynn needs to throw out whatever he has and let the pieces fall where they may. I do not care who cops it over it. I think it should all come out.
You do make a good point though. Because he is under oath and irrespective of whether he has immunity from prosecution or not, how do we know he is telling the truth?