Why, if the left hemisphere is affected, the right side of the body will not work well?

The nervous system controls the work of the whole organism. Specifically, the cerebral cortex. Conventionally, impulses move from the left and right sides of the body. With some exceptions (organs of vision), impulses from parts of the body are directed to the brain and back crosswise. That is, from the right side of the body, impulses go to the left hemisphere and back, and from the left side of the body – to the right. Therefore, if the left hemisphere is damaged, the control of the work of the right side of the body is impaired. This part of the body does not work well.