No, they do not know, and no one will understand how the prophecies will happen. I can assure you they are real and you need to trust your Prophet(SAW) and trust Allah(SWT). In the Quran we often say 'Sadq Allah Al 3atheem', or 'Allah the Great Spoke the Truth'. Indeed Allah(SWT) spoke the truth and he promised Mohammed(SAW) and this Ummah. With regards to those others, they believe religion is backwards and that they are successfully pushing people away from it. So they do not know anything, and don't believe any of those prophecies. And they think they are doing the right thing and bringing humanity forward. It's not that they know any sort of thing and want to prevent, certainly not.Do you think that one of the reasons for this war could be that others know that, and therefore they have preemptively striked against the Middle East in order to prepare for that moment? And does that reaffirm your belief?
They are not going to oppose the Mahdi initially. It's the opposite, world will give up on the Middle East at that time and let him do his thing to stabilize it. Anyway, back to topic now.