The worst part of these accusations is that your reputation is tarnished whether you are guilty or not. This instilled a sense of fear in every person even if they are innocent because you can still be targeted and your career ruined. If this scientist was just stating out, rather than already established, he would likely have had to quit science. There should be some penalty for false accusations that can compensate…
He can certainly sue the US government for accusing him publicly without enough evidence to prosecute, and the resulting loss of compensation. Now, it's not exactly affordable for him to do so. But that's a separate problem we should solve.
If you value doing science and inventing things and mentoring students and the prestige that comes along with it, simply getting a payday isn't anything like justice. Of course, such lawsuits serve more than simply attempting to actually get justice (which is usually impossible) but to dissuade the state from doing it again to others.
Which is cold comfort when all you wanted to do was play with heat transfer. He said he doesn't even want to apply for grant funding anymore, and I can't blame him. You don't become a professor studying heat transport because you're psyched to go toe to toe with the department of justice over made up nonsense that already wasted a year of your career directly and screwed up decades of accumulated talent and reputation.