I was hit by a drunk driver. The officer arrested him. How do I open the claim with his insurance? Apparently he is at fault. So I should not pay the deductible.
You did not file a claim with the insurance of the other person. You sue the other person and not the insurance company. If you sue the other person, not the insurance and insurance of the other person of his choice, either you pay or go to court and let a judge decide how much should you pay. If you refuse to do it right and pass on an application for a claim with the insurance of another person, without pursuing the other person, or you sue the insurance company instead of the person, then you pay nothing.