These symptoms are very concerning. Your father has a very significant history of heart disease, and we know that he already has very bad narrowing of his coronary arteries. Therefore, any heart related symptoms, such as pain or spasms could be a sign that that narrowing is getting worse and that he is not having good blood flow to his heart muscle.
Therefore, I think it is very critical that he gets in to see his cardiologist
immediately for an evaluation. If he cannot get in right away to see his cardiologist, then it would be appropriate to go to an emergency room for a more rapid evaluation.
His cardiologist will want to run some tests, including an electrocardiogram and some bloodwork, looking for any evidence of a heart attack. Even if those tests are negative, he may need a repeat cardiac catheterization
to look at the flow of blood in his coronary arteries and determine whether or not he needs another intervention (like a stent) to open them back up.
The important message is that it is critical for him not to wait and see what happens, but rather to seek medical evaluation as soon as is humanly possible.