Sorry to disappoint, but there is no specific reference to the Brexit event in Biblical prophecy.
There is of course parallel times to that of the Old Testament times and the current dispensation we currently live in. The Jews left Egypt and the Gentiles leave the world behind when we accept Christ. The Jews had a King and we have Jesus. The Jewish nation split into 2 and the Church is split into carnal and Spiritual. The Jews went into slavery in Babylon and the Church will go into spiritual slavery at the end times.
Some false prophets attempt to equate ancient OT lands and nations to current nations and natural events in Israel or they attempt to apply OT Jewish tribes to current nations, but this is all false. Everything in the natural OT times now has a spiritual equivalent. The tribes now represent different types of Christians who have not fully yielded to the Spirit of God. The surrounding nations represent different spiritual authorities which can exercise power over Christians. So when Moab (pride) attacks Judah, this means the church is filled and overcome with pride in a particular point in time. When Moab kills the people of Judah / Israel, it means pride has overcome them and caused they to fall out of the faith.
When the nation of Israel fell to Assyria in 722BC, it indicated that there would be a time when the carnal church, that part of the overall church which is not Spirit led, will become enslaved in an end time world system, which is a Kingdom of one of the beasts as prophesied about in Daniel. In fact we are at this particular point in right about now. A blindness is coming to a large portion of the Body of Christ and a falling away will take place.
What is this deception? It is the ecumenical movement / interfaith movement which is a demonic doctrine that is going to bring much of the church into bondage of the world system. True doctrine will disappear and false doctrines will arise separating Christians from God. In its place will be an interfaith version of the gospel that ties all faiths together, but which is opposed to Christ. This movement will increase continually until the defeat of the carnal faith is complete.
Does Brexit mean anything then? Well it means that Egypt (which represents the freewill of people) is still functioning and able to be exercised. There will come a time when Assyria overthrows Egypt and people will be totally bonded to another world authority, the New World Order. Eventually this hidden world power will take authority over much of the freedoms of choice people currently have, which parallels the time when Egypt fell to Assyria.
The evidence of this hidden world beast power manifests in the following ways: democracy, synthetic medicines (pharmakia), sport, travel, homosexuality, multiculturalism, commerce and trade, finance and banking, among others. This beast is the same as that of Assyria and Grecia and the manifestation are similar as well. Not that all these things are bad in themselves, but it is the tools by which this beast exercises authority over humanity and separates man from the will of God. During the reign of this beast, 4 different opposing powers arise and compete for authority with 2 eventually contesting for total control. This can be seen in Daniel 11 and the equivalent of this today is that capitalism and communism.
Ultimately we will be left with a privatized world government system that that will overthrow the freewill of man, bring a large portion of Christians into spiritual slavery and prepare the way for the end time Babylon system of the UN. Meanwhile ignore all the false prophecies on Brexit.