FatimaF,
There is no absolute contraindication to living at a high altitude with hypertension. However, there are physiologic changes in the body that occur with the transition mostly due to the lower oxygen tension at the higher atmosphere. Usually, the body acclimates over several weeks to adapt to the changes.
Strong contraindications to air travel or moving into a higher altitude by coronary patients include 1. New-onset angina. 2. Unstable angina. 3. Frequent or high-grade ventricular ectopy. 4. Severe or poorly controlled hypertension. If these were the case, they should be addressed prior to the move.
After the move, it would probably be useful to use frequent monitoring of his blood pressure to make any medication adjustments that might be required.
good luck