Bill C asked me to go somewhere with him related to his business. We were in his car and talking as he drove. He pulled up to a stoplight. He continued talking as we waited for the light to change. He turned and looked at me and then paused, tilted his head down, closed his eyes and then dropped his head back against the headrest. At first, I thought he was just pausing to think before he continued. Then I realized that something was wrong, that he had passed out. The light changed so I crossed my leg over and pushed his leg out of the way and off of the brake. I took the steering wheel as I put my foot on the gas and steered the car off to a gas station. I pulled up right next to the front of the building, with the driver's side of the car next to the building. I rolled down the driver's side window. Through the window, I saw two employees. I was yelling "call 911," "call 911." As I did this he came to, so I told the employees never mind.