I'm glad for the exhaust.
I'm so sorry for your wife. It's good though that you discovered that she has the problem. Now all you have to do is convince her to let herself treated, to go to the doctor and take proper medication.
Tell her I insist for her to go see a doctor. And I have diabetes for 29 years, aged 14 at the time.
At that value you can go with her to the emergency, you should go, I insist that you do. First of all she gotta be diagnosed, to know what type she has, Diabetes type 1 or 2. With that high blood sugar it's very possible to be type 1, but it also might be type 2. She gotta know and receive adequate treatment.
For type 1 you gotta take insulin, daily. Otherwise you die very quickly (about a couple of weeks), there's no way around it. This is what I have and I'm taking it every day. I've got used to it very fast and learned how to take care of myself. I'm feeling very fine, good health and all good.
For type 2 they give either insulin too, or some pills. It is also not to be left untreated, although it dosen't kill so quickly it damages a lot if left untreated.
Either one it is you gotta learn how to and maintain the blood sugar levels normal, or as close as possible to normal.
Tell your wife I wish her all the best and to let herself get help. She really needs it. And she will feel a lot lot better on normal blood sugar levels.