The DNA match that the author claims is very suspect. Here is a good article about why. The bullet points are:
Shawl:
There was no contemporary documentation that the shawl was recovered from the crime scene
There was no contemporary documentation that the Inspector that supposedly took the shawl and gifted it to his wife was at the crime scene
The shawl was silk and had an expensive design making it unlikely that Eddowes would have owned it
DNA:
The DNA collected and compared was mitochondrial DNA which is far less unique than nuclear DNA, mitochondrial DNA is generally considered exclusory rather than inclusory
The shawl was not kept free from contamination, descendents of both the identified victim and the identified suspect are known to have handled the shawl prior to testing
On top of the problematic DNA match from his last book the author is now layering on conspiracy theories concerning Freemasons and antisemitism for his new book to draw even more questionable conclusions.
I'm sorry, do you mean shawl? I've been having a hard time reading and understanding things lately, so I tried Googling "shaw" and found a bunch of people named that which is extra confusing in this context