You require at least a low level of insulin to keep metabolic systems in balance. Whether they eat carbs or not, T1 diabetic patients need insulin or they will go into diabetic ketoacidosis and die. Because insulin necessarily lowers glucose in addition to suppressing ketoacidosis, T1 patients need carbs.
T2 patients are on a spectrum with some having enough insulin production and sensitivity left that they can do okay with no/very low carb intake and may even get better as they lose weight. Some T2 patients get a kind of burned out pancreas and severe insulin resistance which requires exogenous insulin to treat and behaves more like T1 but with the caveat that due to reduce insulin sensitivity, they usually need much higher doses in insulin than T1 patients.
T2 patients are on a spectrum with some having enough insulin production and sensitivity left that they can do okay with no/very low carb intake and may even get better as they lose weight. Some T2 patients get a kind of burned out pancreas and severe insulin resistance which requires exogenous insulin to treat and behaves more like T1 but with the caveat that due to reduce insulin sensitivity, they usually need much higher doses in insulin than T1 patients.