To "get on someone's case" means to criticize or harass them.

It means that everyone is criticizing him.

Hello, I agree with Elena. "to get on someone's case" can also mean "to hassle" or "to give a hard time"

'To get on somebody's case' means 'to nag/pester someone'. You keep telling them to do something. "My mum is always on my case to clean my room." "My mum keeps telling me to clean my room. I wish she would get off my case"