Virtual Reality technology and content is evolving very fast and there will be a wide variety of experiences that can be educational and will also enable children to eventually travel and to get sharing experiences with their parents, family and friends as if they wouldn't be isolated inside the room during the chemotherapy treatments...
Currently VR headsets come with a warning saying that children under 12 could experience an impact on certain brain development related to spatial reasoning or something along those lines. It may not be that big of a deal but currently it is not advisable. Oh I need five more words
Kids' body and mind tended to be curious, and having nothing interesting may make them bored too much. Maybe virtual reality is a key. However, there is a possibility that sick kids who played enough games in virtual reality, then may desire to go outside, to feel the World which surrounds them.
These kids whose health status does not allow leave a hospital or chamber may feel pain or envy because of their illness or disease. In this case ambition to sea the world that is in virtual reality may affect kids negatively