I don't know what he does, but this is a case of "when people tell you who they are, believe them". There are some products that he relies on heterim not accepted by most, but otherwise no reason not to rely on it. He definitely doesn't eat OU tuna.
The current discussion reminds me of my FIL A"H's vort מ'האט אויפגעהערט עסן כשר, און אנגעהויבן עסן הכשרים.
@Mods, May I suggest that this discussion gets pruned from this thread and gets its own thread (possible title: Ne'emonus, Eid Echod, and Chezkas Kashrus regarding kosher status of food)