Computers, no matter how good they are, are not designed to tolerate extreme changes in electricity, especially spikes.

An APC regulation box? Is that some kind of uninterruptable power supply? If so, make him set it up now, before another power-out!

In those conditions, I would not even think of running a computer without a UPS. Some just provide protection from spikes and surges, while some provide 5-20 minutes of battery power to shut down and save what you are doing. He needs one of these.

You don't owe him anything. Tell him to get it fixed, then plug in a UPS.