[Mary A]

My DH has type 1 diabetes and hypertension. I'm presuming your DH diabetes is not treated with insulin?
Always carry medication in hand luggage, in original boxes with a copy of repeat prescription. Take more than he thinks he will need in case of flight cancellations etc
Carry high sugar sweets - DH is finding the small packs of skittles perfect for times when his sugars drop
Carry some items such as granola bars for longer acting sugars and for when he feels he needs a snack
Obviously, Drink plenty of water to stay hydrated
DH does not order a diabetic meal preferring to eat a normal meal but maybe leaving some of the carbs (he never eats the bread roll) and adjusting his insulin accordingly
He wears flight socks

Enjoy your holiday!
Eta - inform insurance