My oldest daughter used to do that. Whenever she would cry hard, she would take a deep breath, open her mouth to scream, no sound would come out and her eyes would roll back in her head, she'd go limp and fall down. After a few seconds, she'd be fine. I had never seen a child do this before she did and it was scary the first time. My MIL says that my hubby did this as a child. I knew what was happening at the time becuase there was couple down the road with a child who did this. My husband is and EMT on the fire dept. and they would always call the squad. By the time they got to the house the kid was fine of course. It happened so many times that I knew the address just from hearing it on the scanner. So when it happened to us, I didn't freak too much. I talked to her dr. about it and he told me to just ignore it and she would grow out of it. They don't do it on purpose, it is a tightening of muscles that doesn't allow them to breathe, when they pass out they relax and they are able to breathe again. As she got older, I was able to sometimes snap her out of it by yelling her name in her face. She would look at me and the focus would change. She finally out grew it when she was about 3. My second daughter did this once or twice, but that was it. #3 daughter has only done it once so far. Hubby was there with me and when I saw it coming, I said to her "oh no you don't, don't you do that to me also." I yelled her name really loud and she snapped right out of it. We laughed about it! We have a really funny story about one of the last times that Alex did this, she was older and she was having a temper tantrum. She started to scream and passed out. We were getting out of the car at the time, I saw it coming and put her on the ground to walk away. She passed out and rolled right under the car! I did what the dr. told me and ignored it, because it was a temper tantrum. When she finally got up, I helped her from under the car. I looked up and all the neighbors were standing there watching. She did it once in a restaurant and collapsed face first into a plate of food. The server happened to see it and was horrified that we just moved her face so she could breathe and let her come to normally. If your son continues to do this, you will get used to it and be able to see it coming. He will grow out of it.