As per :

https://www.nzherald.co.nz/entertainment/so-long-jack-reacher-why-lee-child-is-handing-over-the-series-to-his-brother/XC5FFLI2XZYTLPRMNXCKRNCP4Q/

He will hand the reigns off to his 14 year younger brother after a period of shared writing which starts with the next book released next month.

I was surprised at the length and detail of this article and was about to commend the Herald for it's first decent bit of writing in some time before I read at the bottom it was taken from the Times of London.

I really hope they can get this done well. I have read every annually released novel released by Child and whilst he does appear to have lost his way in recent times compared to earlier work, the last book was a bit better.

I had pleasure in meeting Lee Child in Auckland a few years ago and was totally stunned when he asked my name and then asked me if I was the guy he had interacted with in his forums a few months earlier. Was very cool!