They can only sue if the goobermint waives immunity, and that isn’t going to happen.
However, a Senate and House investigation, together with DOD and independent investigations might get to the root of this.
A Dem controlled PC House and a Dem controlled PC Senate and a Dem controlled PC DOD will expend their energies on a cover-up, not on getting to the truth. It will be worse than the 911 Commission. Independent investigations will be denied access to relevant information. Maybe Sandy the Burglar will be called in if someone gets too close to the truth.
The truth is not the friend of our government, including the present military.