I'm afraid that is incorrect, type 1 diabetes still have glucose metabolism, with diabetes type 2 glucose metabolism could be impaired but with type 1 that is not the case.

What has changed is that without insulin glucose will stay in their blood damaging organs and veins.

Insulin signals to cells take up glucose and other nutrients, first organs like the liver, then the muscles.

More information in the link from healthline. https://www.healthline.com/health/diabetes/insulin-effects-o...