No overnight stay is needed on this agency border run. This route has been in operation for many years, I first did it in 2003. You will be stamped back in again no questions asked.
He is in the same position as those of us on soft power and the course has finished. To extend in country he needs proof or just do a border bounce for a new 180 day stamp.
I never used it I just asked if they did. However the chap who was previously on an Ed visa and had to pay 20K entry fee at swampy probably wished he used it.