HI Thank for asking to HCM I really appreciate your concern, if he is type one diabetic patient then he has to be very careful in controlling his sugar level there is certain rules for this and that has to be followed for a better control of diabetes, glycosylated Hemoglobin test is very important (HbA1c) this gives the diabetes control status here I am giving just guide line that could help him but for better understanding he need to see the physician, long acting insulin is preferable in morning dose and evening dose (Bed time ) while rapid acting insulin is good for before meal dose, again the combination also matters, carefully choosing the insulin and the best clinician takes good care for this, hope this information helps you have nice day.