Sounds like he needs a medication review. Honestly, at those levels I'd personally regard the UTIs as a potential symptom of the high levels. They are likely to keep recurring until his levels come down. Mine have usually cleared up on the first antibiotic dose but I used to get them quite frequently in the days when my diabetic control was mediocre (dare I say poor). And high sugar levels will cause tiredness as well, so though there may well be something else going on (I am not a doctor and we aren't allowed to diagnose on these forums) getting his sugar levels back to normal is very important.
T1 seems unlikely to me after 20 years of T2 without needing insulin, but I am not a doctor, and there are also other types of diabetes (eg MODY, T3c). Some long term T2s find that their insulin production wears out so they need to start injecting. His doctor will look at his medication options. It's likely that reducing the carbs in your diet would potentially allow him to cut back a bit on any medication he is using, but at the moment those levels are too high, and need reduction.
Good luck.