What happens if the power goes out (tree falls on line or something) while he's gone?I speak from experience here: The best thing you can do if you have to leave a residence for days or weeks, is to set up electric space heaters all over the house, maybe four of them. Set their thermostats to come on if the temp falls below 50. Then set your house furnace to 60 F. If your house furnace fails for ANY reason, the house temperature will gradually fall to 50 F, causing the space heaters to pick up the slack and prevent your house and plumbing from freezing.
You can monitor your house temps remotely in a variety of ways. It is no longer important to monitor temps continuously, because this system is fail-safe. It's sufficient to check the temps once or twice a week.
Since most space heaters just have a rotary dial temperature setting without numbers, I calibrate them in my garage near 50 F and tape or ink a mark on the knob that corresponds to 50 F.