In the Ambalatthika-rahulovada Sutta, while giving instruction to his son Rahula, Buddha said that, “when anyone feels no shame in telling a deliberate lie, there is no evil, I tell you, he will not do.
If we study about karma, the results of negative karma in that first there are the main result, a similar result, a reaction result, and a place or condition result.
If one examines the cause, then there is a direct result of that cause. In the case of lying, the direct result would be being lied to or being blamed unjustly. There would also be a similar result, meaning that the direct result would occur in conditions similar to the original cause. Then there would a reaction effect, meaning that there would be the development of a habitual tendency to lying – which in this case of your friend, has become so strong. The effect of place and habitual tendency associated with lying could include people failing to believe anything the person who lie told them or being wrongfully jailed without guilt.
Unfortunately, there is no other antidote besides being very truthful in all matters, practicing Right Speech even to her detriment, and only she can make this choice. Because only by applying this antidote, she is able to change her habitual tendency of lying and stop creating negative causes which produce suffering for herself. It takes a lot of hard work to purify negative habitual tendencies, but the results are worth it as it will not only reduce our own suffering, but the suffering we cause in others we lie to or about whom we lie.