Camera batteries?
It's a movie, sometimes there are plotholes, I know. But what about power for the cameras? I'm no expert in spy cams, but considering how tiny they were, I'd be surprised if they had batteries that would last longer than one or a couple of hours. And this project was supposed to last for six weeks? Granted, they had motion sensors, but there was still a load of footage throughout the movie and most of the cameras would capture the old man for a bunch of hours each day.
Now shame on me if this was explained and I missed it, but it actually bothered me since it makes everything impossible?!