The demographic displacement of Europe, primarily Western Europe, has been extensively written about. The following article gives a summary of some more recent thoughts about this, putting the “great surrender” down to a type of civilisational exhaustion:
  https://www.gatestoneinstitute.org/12093/europe-civilizational-exhaustion

“Stephen Bullivant, a professor of theology and the sociology of religion at St Mary’s University in London, recently published a report, “Europe’s Young Adults and Religion”: “Christianity as a default, as a norm, is gone, and probably gone for good – or at least for the next 100 years,” Bullivant said. According to Bullivant, many young Europeans “will have been baptised and then never darken the door of a church again. Cultural religious identities just aren’t being passed on from parents to children. It just washes straight off them...

“And we know the Muslim birthrate is higher than the general population, and they have much higher [religious] retention rates.” Richard Dawkins, an atheist and the author of The God Delusion, responded to the study’s release by tweeting to his millions of Twitter followers: Before we rejoice at the death throes of the relatively benign Christian religion, let’s not forget Hilaire Belloc’s menacing rhyme:

Always keep a-hold of nurse
For fear of finding something worse.

Dawkins is apparently concerned that that after the demise of Christianity in Europe, there will not be an atheistic utopia, but a rising Islam. That is the major point of what Philippe Bénéton in his book The Moral Disorder of the West (“Le dérèglement moral de l’Occident”): Islam is filling the cultural vacuum of a society with no children and which believes -- wrongly -- it has no enemies.”

     White racial pathology though, is surely only part of the problem, even if the major part. There is always the problem of the enemies within the gates, who now control the entire security system, and lifeblood of society, a faceless group of elites, loyal only to abstract notions of money and power. And, there must really be a problem if atheist materialists such as Richard Dawkins are worried.