Say whatever you want about WWE, they are not letting Edge do physical shit if there was a reasonable chance that this was going to blow up in their faces and make them look careless. I don't know if it's time, therapy, experimental treatments or luck, but Edge is cleared because he's cleared. When they look at his neck they are not seeing a guy that shouldn't be taking bumps anymore.
Just like Daniel Bryan. There were a few people who were cringing every time he did something, and yeah, I get it -- but WWE are not going to put Bryan out there if his brain displays any sort of abnormality that is going to destroy them if something horrible happens.