So you didn't watch all the evidence and you clearly have no idea how we breathe. They were able to count the breaths from watching the video.
When you breathe in, your chest expands, your diaphragm contracts and flattens so creating a void and so a low pressure in your chest cavity. As the atmosphere outside is roughly at 1 bar and higher than in your chest the air rushes in to the lower pressure void, you breathe in, the air entering your chest is never above 1 bar. With weight on you like FG had on him his chest couldn't expand fully, so he had problems breathing in properly. However when you breathe out your muscles are able to force the air out which is why you can blow up a balloon, which is also why he was able to say he couldn't breathe properly. He wasn't getting enough air but that is still enough air to say you can't breathe. I'm fairly sure you were one of the people who said he watched the trial and there wasn't the evidence to convict. Clearly that isn't true.