It certainly could! He cannot take many hits - or, well, his species typically cannot! I have not seen him in such a serious fight since we got here.

[Serious in tone, certainly, but the Swoobat didn't come that close to knocking Emmet out!]

There are also some Pokemon that have special abilities that can allow them to strike a ghost! In battle, things are rarely entirely clean-cut - there are always strategies one can employ to counter even significant advantages!