There isn't a magic number where suddenly, things go 'bing'.
A coma from DKA has nothing to do with blood sugar levels and everything to do with circulating insulin levels combined with ketone levels. It is extremely rare for a T2 to go into a coma from 'high blood sugar levels' although there is a situation known as HONK where this can happen.
High blood sugars almost never cause a seizure. The danger facing a T2 is more of a slow burn - it's the gradual damage caused to your body from high blood sugar. High being anything over the normal range. You could potentially have a seizure from low blood sugar but it is a heck of a mixed bag as to when this happens. Some people completely lose it the moment their blood sugar goes under the 4.0 (72) mark. Meanwhile, I've been walking and functional with 1.3 (24).
Your body is an organic, analogue system. Your meter has a 20% margin of error. The blood sugar level in your fingers will be different to the blood sugar level in your brain anyway. So it is impossible to define exactly where the boundaries are.