Ugh. I didn't realize you are dealing with DV with your partner on top of all of this. It still seems like the first thing that may need to happen is to find a different doctor to work out his meds if this is primarily a med sedation issue; that can be worked out.

Write a letter giving you permission to get to the car and wake your partner up long enough to get him to sign it. Towing companies are such a racket. If the insurance company totals it, just leave it up to the insurance company to dispose of it and take care of the fees, but I understand the need to get the hearing aids. Last car we totalled we never did get all of our stuff out of the car but none of it was as expensive as hearing aids either.

You probably won't get anywhere in taking on the doctor. Most likely the prescription was marked for sedation which pretty much means if your partner drove when the warning was on the script, that responsibility sits on his shoulders. Just find a different doctor to work with from here on out.