The year 1914, which is the year that the Gentile Times (aka Appointed Times of the Nations) ended, was determined though a study of the Bible along with no doubt some holy spirit given to the brothers that were able to discern this information.
If this person actually said this, then they are sadly ignorant of the history of their own religion.
The 1914 date was entirely the work of the Second Adventist Nelson Barbour. Barbour detailed his application of the 2520 years leading to 1914 in the September 1875 issue of Herald Of The Morning
This was before he had ever met Russell
Charles Taze Russell, by his own testimony (cf. Zion's Watch Tower June 15 1906) did not accept either the 1874 or the 1914 dates until he was convinced of them by Barbour in January of 1876