Is it permissible to lie to a liar so that he may understand and abandon lying, even if this person is a hypocrite and a liar?

Sins are not to be treated with their likes. Lying should not be countered with lying. Rather, the liar should be advised and admonished, and the ugliness of lying should be explained to him, as well as the fact that it is a grave sin and a characteristic of hypocrites, and that it negates faith and leads to immorality.

He can be boycotted if boycotting is beneficial, or his matter can be referred to the administration to take a deterrent measure against him.