Dealing with a Difficult Boss
A boss might exhibit dictatorial behavior, similar to historical figures like Hitler or Saddam, with violent tendencies. If he is a leader, the approach could be different. It is wrongful on his part to shame an employee in the presence of other colleagues, as this will further distress the affected employee. Instead of working under such a person, one might as well consider staying at home, doing nothing.
Handling Mistakes and Encouragement
Making mistakes while performing jobs is inevitable; it happens to everyone. Nobody is perfect. The affected individual can be encouraged to quit and join another company where there is a positive environment for learning and working, where efforts are appreciated, and where guidance, coaching, training, and motivation are provided.
Developing Assertive Skills
There is no need for the employee to prove their medical fitness or otherwise. Even if there is a loss of ten days' salary, it does not matter. Let the individual develop assertive skills, communicate their views clearly and properly, and not allow themselves to be bullied by bosses. Such bosses may not last long. One fine day, a smart individual will emerge from the crowd, turn around, tell the boss to get lost, and walk out!
Best wishes