Entirely depends on which country within Europe, France for example has employment laws which are incredibly favorable to employees rather than employers.
The story happened in Belgium, and the specific duration in this case would be three months, unless there are some specific details that we are not aware of. I agree that it would have been different in another country.
That depends. New hires go through a probation period up to 4 months renewable (almost always renewed in practice) were you can be fired in a couple days without justification.