All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad is His slave and Messenger.
This story happened in the previous nations before the advent of Islam, and that man was a Christian monk before Islam as it is evident to you.
As regards telling lies, there is no doubt that it is forbidden but if there is no other means to repel a harm from one’s own self or from others except by lying, then it becomes permissible to do so in this case. For more benefit, refer to Fatwa 88412.
With regard to the monk who foretold what may happen in the future, then he may be inspired by Allaah and he might have known this based on what happened in the Sunan (plural of Sunnah i.e. rule or way of dealing) of Allaah in this universe as a way of testing those who are upon the truth.
Allaah Says (what means): {Do the people think that they will be left to say, We believe and they will not be tried? But We have certainly tried those before them, and Allaah will surely make evident those who are truthful, and He will surely make evident the liars.} [Quran 29:2-3].
Moreover, Sa’d ibn Abi Waqqaas narrated: ‘‘I said: ‘‘O Prophet of Allaah, who are the people who face the toughest trials and hardships?’’ Thereupon, the Prophet replied: ''They are the Prophets, then the most pious people (i.e. scholars and devout worshipers) and then those less than them (in terms of piety); a person continues to be afflicted according to his religion (i.e. the level of his piety and how patient he is): if he is firm in his religion, he is greatly afflicted, but if he is not strong in his religion, then he is afflicted according to his religion, and the affliction does not leave a person until he walks on earth without having a sin (on his record of deeds).'' [Al-Bukhari].
Allaah Knows best.