All this what is happening is self-evidently well organising
In various regional dialects of English what can be used as a relative pronoun in relative clauses modifying a noun phrase:
- [That elephant] [what we say yesterday] was amazing.
In standard American, British and Australian Englishes, this isn't possible. We only use relative "what" in free relatives or what the Cambridge Grammar of the English Language call fused relative constructions. This is when we get a relative clause with no antecedent noun or pronoun:
- [What we say yesterday] was amazing.
Here the word what stands in for the missing antecedent noun as well as being part of the relative clause itself.
If there is an antecedent noun phrase in standard English, we use that or which- or if the antecedent is a person, we use who:
- The dog which bit me ...
- The dog that bit me ...
- The doctor who saw you
The Original Poster's sentence comes from a piece of writing which uses standard English, not a regional variety of English. This sentence would appear to contain a typo. Having read some extracts from the authors work here, there would seem to be two possibilities. One is that the author has simply used a W where they should have used a T. However, the second, which is perhaps more plausible, is that there has been a punctuation error. The phrase what is happening might be a parenthetical Adjunct which should have been set off by commas or dashes:
- All this—what is happening—is self-evidently well organising itself.
In other words it means:
- All this, the stuff that is happening now, is self-evidently well organising itself.
The author's other extracts seem to have similar punctuation irregularities, but they don't seem to effect the intelligibility so much.
The entry for what used as a relative pronoun with an antecedent is given in definition 2 here at the Marriam-Webster Dictionary
2 chiefly dialect : that, which, who