those are not symptoms of nerves acting up . Only half of those who have a heartattack survive ...your dad could be one of those, because right now he likely has a blockage which is only going to get worse , the rest either crumble in pain and only have limited time left , or stand there smiling and the next moment fall like a tree .
Tell him he has one heart the more the damage the earlier the death . It takes only up to 20 minutes for a bad clot to travel to that place called the heart obviously that clot is close and has very little distance left to travel...if it breaks free and ends up in the wrong place , you bet he'll drop .
Have ASA (aspirin) handy (just incase) make him take up to 4 regular strength immediately if he has these symptoms and cart him off to ER really I'm not a doctor , but thats the advice I've been given and if you look at videos on this forum you will see proffessional advice which mentions taking asa .
It may not be a bad idea to have a little 4 dollar spray container of Nitro in his pocket . Neither choice is alternative advice over getting him to the ER or doctor but its going to have an enormous impact on his survival if he does have a heart attack the other alternative is CPR(there are no other alternatives) until he gets a clot buster (about $3000.00 for the clot buster) and supposedly the clot buster can only be used once because a second will likely cause a person to bleed internally to death but they work almost 100% of the time ( for clots only don't mistake that for a tired ,weak ,lazy ,enlarged or poor electrical impulse of a heart )
Considering all this... he is playing chicken with his life , not a good idea when it comes to literal matters of the heart .I did not receive a clot buster because I think they were saving it as a last hope but I did get loads and loads of nitro pumped into me over 10 hours I had a heart attack and they performed angioplasty with stents (small tubes in the blocked vessel ) I digressed so much that nothing was working so the operation was my only chance. You can survive on only a portion of your heart but that means heart drugs everyday of your life and it makes you very weak even a small amount of heart damage changes you .