Claim reopened?

Last year in April I had an accident where I was getting off the highway and making a left turn.

This is the story: The light was red and there was a car in front of me and I thought the car pulled off since he moved up. I messed up and let go of my break and it hit his car. We both got out and I apologize and asked if he was okay and he said yes. So we exchanged information and then at some point he started saying he was hurt. Since I was scared I told him I’d call 911 to get him checked out and file the accident. At first he told me no but I told him yes since I didn’t want him driving hurt. They check him out and he was fine.

I thought it was just going to make my insurance go up to pay for his damages. But later that day or week I got a call from my claims agent telling me that the man was hurt and wanted to use his bodily injury claim and it also made my insurance go up. I was paying for my insurance like normal for a year but yesterday I got a letter saying that the guy had to get surgery from the car accident and that I need to contact the insurance company to settle this. I find this strange cause this happened a year ago and it wasn’t much damage done to either cars. My question is why is how can he do this a year later?
And will it be a long process to deny his request. I’ve tried contacting my agent but since it’s the weekend I can’t get a reply till Monday and I’m just so anxious to know what will happen.