What should we do with a father who continuously lies and denies his lies, under the pretext of "brain drain"?

Effort must be made to advise those accustomed to lying, and to explain its danger gently and kindly, for it brings much evil in this world and the hereafter. Among the warning texts is the saying of the Prophet, peace and blessings be upon him: "And indeed, lying leads to wickedness, and wickedness leads to the Fire. A man continues to lie and strives to lie until he is written with Allah as a liar." Lying is doubt, while truthfulness is tranquility. Ibn al-Qayyim swore that truthfulness is a sign of the fortunate and lying is a sign of the wretched, and that Allah destroyed those He destroyed by lying and saved those He saved by truthfulness. Truthfulness is the best blessing after Islam, and lying is the greatest affliction to it.