Hopefully your DH and everyone else is okay.
While Britax does allow reuse of a restraint in a minor crash, that crash does not meet the definition of minor. In order to be reused, the following five must all be met:
No injuries
No airbag deployment
Vehicle door closest to the restraint is undamaged
Restraint is undamaged
Car is able to be driven away from the crash.
So your seat must be destroyed and replaced. Hang on to it until you find out what insurance wants you to do with it; sometimes they want to keep the seat, sometimes they let you dispose of it. Usually the responsible party's insurance will pay. If not, you can try with your own insurance, or sue the other party directly (if they were at fault) for destruction of personal property.
If you're allowed, you can keep the cover and reuse it or sell it. Same with the harness covers, belly pad, and since it was unoccupied you can also keep the harness, crotch buckle, and chest clip. Then, take a permanent marker and write on the shell "Dangerous. Do not use." Put it in a black trash bag so it's not obvious what it is and dispose of it (recycle if that's available, otherwise trash).