No doubt he does. In other countries (mainly Australia and the US) around the world concussion is an automatic stand down from playing and training anywhere between 10-14 days. In Greece it is take the weekend off levendi and we'll see you on Monday!
Just on a sidenote, it is an area in which football does lag behind in other sports. Concussion is a huge issue in sports and while not as prevalent in football, it is something that isn't really taken as serious. I know a few years ago the EPL that had introduced an extra sub for a concussed player but I am not sure that is a thing anymore.