Hi,
I apologize for the delay in my response. By now your Dad is likely out of the ICU.
Most likely he had hyperglycemic hyperosmolar state, which is one of the serious acute conditions that can occur in diabetes(diabetic ketoacidosis is another--the doctors taking care of your dad should know which condition he had when he was admitted). Both conditions are quite serious and definitely require hospital care, so I am glad your dad went to the hospital. He has a good chance of needing insulin later but this is not absolute. Sometimes an infection starts a cascade and leads to this kind of problem, but after everything is treated people sometimes go back to oral medications. He should definitely be seen by an Endocrinologist while he is in the hospital, and after his discharge.
Please let me knw if you have any other questions.
take care.
My dad is 57. They are giving him insulin every hour until it goes down.
Your Dad is lucky to have not gone into a coma. I think since he is in ICU that they will give him Insulin for sure. And get him out of danger. hopefully his kidneys and heart are ok. That is dangerously high. He will most likly be on Insulin after he comes home. How old is your Dad.