Because Federal prosecutors were vowing to go after Flynn's family. It is a tried tactic of vermin prosecutors, like that snake Andrew Weissmann who was Mueller's "pit bull" and who went did the same thing to innocent people in the Enron and Arthur Anderson cases.
Will Michael Flynn Plead Guilty And Cooperate To Protect His Son?
Barr's "review" of the case has been late, weak, and ineffective.
I don’t dispute any of that. I understand why someone in Flynn’s shoes would make a plea deal in that situation. What baffles me is why he’s still around more than two years later trying to undo everything he’s already done.