Hi,
Sudden severe stress can raise blood sugars, but levels that require treatment occur mainly in people who are predisposed to diabetes in the first place. A blood sugar of 600 certainly requires treatment and makes me think your husband has had some early pre-diabetes prior to this time. It is also important to consider any medications he was given during this time as certain ones can also raise blood sugars.
I cannot say if there are any other surprises headed your way; the best thing to do ofcourse is ensure your husband gets his diabetes treated , starts on a healthy diet and exercise plan, and stay in close contact with his doctors so nothing is missed. Take care.