I felt the need to respond. I've been insulin dependent for 54 years. Anxiety is OK. After all these years I still get anxious at times but experience in knowing how to deal with insulin treatment as reduced that a lot.
You most likely have been told she should keep her glucose numbers between 70-180 (as recommended by the ADA) or some other range suitable for her. Just remember this is what to TRY for most of the time. No insulin dependent patient can achieve that 100% of the time, so don't get anxious about that. It is not possible, especially when first starting out and then ever. High glucose readings for days on end will contribute to complications. High for a few hours I wouldn't worry about. Anxiety about low's is a good thing. They can get to be on the serious side rather quickly. Trembling, sweating, and disorientation should be treated with glucose tablets, juice or other fast acting sugar and should always be carried with you. As long as she can eat/ drink it, blood glucose will come up, may take 20 minutes, but it will come up. If it goes high as a resul, then treat the high.
She should have been given some guidelines such as 1 unit of fast acting insulin will reduce glucose about 50 points. 15 of carbs will generally raise it about 50 points.
And don't fall for, what some doctor's will say, "You only need to check glucose before meals and bedtime." Biggest piece of BS advice ever given!! Check as often as YOU feel necessary. If not feeling quite right, check it. So what if one is checking 8-20 times a day. One is learning to deal with diabetes and one needs that information. With information one is not stuck eating boiled chicken breast and kale the rest of their life!
Technology can be a big help but with the basics one can live with this disease. IMHO
The best to your wife and you. And thanks to you for caring so much. It helps to have a village.