Just out of curiousity, if he captured random bugs from his yard, why do you automatically assume it's brett? There are lots of different strains of wild yeast around, although brett isn't uncommon.
Not sure where this guy is from but I heard on TV that the ohio valley area has the largest concentration of wild yeast and mold in the entire country. Probably because it seems to never quit raining here. They claim there are "many" different strains.