There are two comments I'd like to make:
(1) His insurance company will first pay him the $15K for car repair, then the insurance company will try to retrieve the $15K from you. Wether or not his insurance company gets the $15K from you has nothing to do with him (the injured). His insurance premium will not go up since he has no-fault, no matter the company retrieve the money successfully or not.
(2) No body can get the money out of your primary residence or retirement saving. However the court can order to get funds from your hu*****and's payroll.