Are Kalimullah, Khairy going to sue Matthias?

Former political secretary to Dr. Mahathir Mohamad and Britain-trained lawyer Matthias Chang has publicly made serious allegations against Kalimullah and Khairy by names which are published in the Oriental Daily, Sin Chew Daily and Singapore's Straits Times.

So, are they going to sue Matthias for defamation to clear their names? Dare Kalimullah and Khairy sue Matthias in court? If they sue, don't they worry more details would be exposed? If they don't sue, don't they also worry what Matthias has said would become TRUTHS in the minds of the public?