So sorry...
It will pass. My FIL passed today 15 years ago. It still seems recent. But no longer painful.
The car is an annoying distraction. If you were rear-ended, it's clearly the other guys fault. It's up to his insurance to make good to your satisfaction. You are not his insurance's customer; he is: the guy that will get sued if you don't sign off. They have to make him happy which means they have to make you happy enough not to fuck with them. Don't sign off on anything until they come to your satisfaction.
The car is an annoying distraction. If you were rear-ended, it's clearly the other guys fault. It's up to his insurance to make good to your satisfaction. You are not his insurance's customer; he is: the guy that will get sued if you don't sign off. They have to make him happy which means they have to make you happy enough not to fuck with them. Don't sign off on anything until they come to your satisfaction.