I’m sure you saw that Ahmadinejad told the United Nations that Al Mahdi was coming back soon in the company of Jesus Christ. Since his side and our side seem to be looking at the same guy and situation through polar opposite filters, doesn’t it seem more logical and effectual that the whole world would be united and deceived through a counterfeit Jesus Christ instead of some apparition of Mary?
Islamic prophecies of Jesus accompanying al Mahdi are similar to Biblical prophecies of a false prophet accompanying the anti-Christ. But Islamic prophecy only has credence to the extent that it agrees with Bible. Biblical prophecies tell us the anti-Christ will claim to be God in human form (2 Thes 2:4). This would put the counterfeit Jesus in the position of pointing to al Mahdi as the real Messiah.
From my understanding of her proclamations, the Marian Apparition appears to make reference to someone she calls her son, and has been encouraging the whole world to unite behind him. I believe this is really a reference to the anti-Christ. If the Islamic prophecy is true, the apparition would have to say that the one calling himself Jesus is not her son after all. I think that would create a huge credibility problem.
Remember, Catholic doctrine holds Mary to be the Lord’s co-redemptrix, assisting in the redemption process by having agreed to birth Him, by suffering with Him at the foot of the cross, and by interceding with Him on behalf of Catholics everywhere. This makes her extremely important to them. Muslims also revere Mary as being at least equal to Jesus in their eyes. And the New Age and Eastern religions all have a goddess they believe to be represented by the Marian apparition. She has substantial world wide appeal, perhaps even greater than one calling himself Jesus would have.