Total economic damage – disbursement ?

Hello, I would like to ask your advice in the following case: My mother-in-law has driven someone into the side of the 15 year old car. The vehicle is still driving, but due to the large side wall damage “economic total damage”, i.e. repair costs were scrapped with approx. 4000 Euro, vehicle value clearly below. Now the insurance asserts that the car is compensated with total 1000 Euro incl. 100 Euro scrapping part, but for that the vehicle In my opinion, however, it can receive more than 100 euros for the car from the local scrap dealer. Can my mother-in-law “reject” the scrapping portion and apply for payment of the replacement value and keep the car or can the insurance here still deduct “other costs” from the replacement value or completely replace it? Unfortunately, I have no comprehensive information on the topic of total damage and processing with the insurance found. Thank you for the help Joe