What is when he says leave me alone?

When someone says "leave me alone," it means that the person wants to be left in peace, and they don't want any company or interference. It is their way of saying that they want some space and time to themselves and they don't want to be bothered or disturbed. Saying "leave me alone" could be due to many reasons, including lack of privacy, feeling overwhelmed, need for alone time, stressed or upset, needing to focus or concentrate, and so on. In any case, when someone utters these words, it is important to respect their wishes and give them the necessary space and time they need.