If it was a rear end hit, your brother should not be at fault. Unfortunately, even non-fault accidents can raise your rate slightly
First, if your brother was injured, he should consult a personal injury attorney.
Second, if your brother was not at fault for the accident, and generally a vehicle that was rear ended would not be at fault (the other car's front hit the rear bumper of your car - not the rear quarter panel), then your rates should not go up for that reason.
I always tell my clients that if they see a rate increase, first call their agents to see if the increase was for everyone or was it because of this accident. Almost always the rate increase was due to some other reason.
Nevertheless, if your insurance company pays for the car to be fixed under the "collision" coverage of the policy and the amount was generally more than $400.00 (check your policy), then your rate may go up if your carrier does not get the money back from the other driver's insurance company (or, if ununsured, from the other driver).
Should you find out that this was the reason for any increase in premium, or that you were charged (by your insurance carrier) with the loss, check that the carrier received notice that the matter was a rear-ender and that they know who the other insurance carrier is. Sometimes they make mistakes, too. You should call with the Claim number and ask for the Subrogation Unit of your carrier. I can think of several clients where after such a call, the premium increase was rolled back. If they still refuse to anything, then you can challenge the increase by filing an appeal with the NJ Insurance Department (which information should be on your notice).
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