This is way too high for a type 2 (I assume that type on the basis of medication) and far above his normal level. Although diabetic ketoacidosis is much less common in Type 2 it can happen. Try and convince him to call 111.
Does he have ketones testing strips? If so check them. If they are also significant he needs to call for help now. If he doesn’t and feels at all unwell he needs to call for help and advice now, not tomorrow.
Otherwise If you can’t get him to call watch the meter closely, do not eat anything with any carbohydrates for now, drink plenty of water, go for a walk (with means to call for help if required) and keep watching for levels to fall. If they don’t or if they rise call for advice.
Did he eat or drink anything that might have caused such a high number (sugar, grains, beer, flour based product, potatoes etc etc) Knowing that he did might be a little reassuring that it might lower in a short while.