Have a friend with a blood sugar of almost 450! how really close is this to getting admitted to the hospital?

Pretty close. Generally speaking in a diabetic with bs over 300, the body is essentially in a state of Insulin deficiency (or lack of Insulin mediated glucose uptake to be precise). There is certainly many individuals who can run in the 300s for weeks and not be terribly sick, however having high unexplained bs, checking urine/blood ketones becomes mandatory and if moderate/high, deserves immediate medical attn.