I am summoned because of an accident that happened one year ago. The owner never reported to the insurance and there was no police report. I told the owner to report now as I am summoned, but he still doesn’t want to notify the insurance. At the time of accident the guy was all right but now he mentioned some injury in the complaint to the Supreme Court. What should I do? Please advice.
I know, I am just trying different scenarios.
Never been through such situations.

You have asked this question 3 times and not sure what answer you are looking for.
A lawsuit has been filed (summons) which means that both you and him are being sued period.
This is not going to go away, even if he chooses to do nothing and ignore it.
You can call HIS insurance company and report this, since the insurance is in the car that caused the accident and you are being sued also.
Or you can hire a lawyer yourself and pay out of pocket.
Or do absolutely nothing, and wait and find out how much the judge awards them and you and him will owe and pay out of your own pocket.
cover your butt get a lawyer more than likely he’ll have one there too
notify your insurance/get lawyer to protect your self/you had the chance at the accident time and then it was easy/always call the cops