Thanks very much for the replies.
Regarding the power lines/transmitters... possibly. He has attempted multiple routes home, and it's occurred regardless of the path he takes. Being in the Bay Area, I'd imagine that there's plenty of lines & transmitters available that could cause this if the device is susceptible.
For the OS/Battery - the device is on 18.104.22.168, but the battery strength is a good call.
I need to follow up w/ him so I'll posit both of your suggestions/info and we'll see what happens.