Possibly, he may have been registered at that address at some point, so in checking for over-stayers, the last known address of him or even his Thai wife if the property is registered to her in any way would be the obvious starting point.
I tried to apply for combination method last year as I was a couple of 00 short one month out of 12 (but well over 1 million on average over 12 month period, but irrelevant), and the IO refused to accept the combination method. He said either minimum 65k a month (no exceptions) OR 800k. This was at Chiang Mai.