Tape the probe to the heat pad on the outside of the enclosure and tinker with the thermostat setting until the inside of the cage reaches the right temp. For mine, the temp ON the pad needs to be 100f for the inside of the tub to reach 90f. If he pushes or pulls the probe off the hot spot it could cause burning hot temps to come from the heat pad.
That sucks. I had tape in my enclosure until reading some wicked horror stories like this on these forums. Luckily I was able to get the tape out before anyone got hurt.
Good luck.
Agreed. If its just hanging out on the inside loose then he could move it or he could dump his water dish on it and send the temps sky high.