Sleeping during work is normal and acceptable in Japan. If in other countries, that would get you fired, in Japan, it is seen as a good sign that shows dedication to the work and that the person worked themselves to exhaustion. The companies may see it as a good thing, but Japanese are the most sleep-deprived nation in the world. People take naps not only at work, but wherever they can. It’s so widespread that there is a word for this phenomena – inemuri.