I'm sorry he doesn't have good insurance.
A general physician or family physician is a good place to start, but he can do something before that which might give him some insight.
And by the way, I'm kind of familiar with this since my dd has anxiety/panic attacks and a heart condition called Inappropriate Sinus Tachycardia which means that her resting heart rate is always above 100 - she takes medication and sees an electrophysiologist.
So, your cousin should do two things right now.
1. Purchase a blood pressure reader at the pharmacy. They're at Walmart and everywhere else and they are easy to use. Don't buy the ones that go on your wrist, buy the one that goes around your arm. All you do is put it on with the little arrow facing the correct way, and push a button basically. He'll see his blood pressure and pulse. Some have a memory button that will record up to a hundred or so readings.
2. Buy a cheap paper notebook and use a page per day. On each page, keep a log or journal. Write down symptoms and what's going on.
Example: 10 am. Drank a large coffee from Starbucks. Haven't eaten since breakfast at 6 am when I ate ______. Tested blood sugar and it's ____. Feeling anxious. Took blood pressure and it's _____ and it shows my pulse is ______. Took 2 aspirin.
12 noon. Had a Quarter Pounder from McDonald's. Walked 3 blocks there and then back to work.
4 pm. Feeling panicky. Sweating and my hands are shaking. Hearing a lot of noise from co-workers and it's hot in the office. I think my blood sugar is off but I haven't tested it.
Keep a constant journal of his activities, what's going on around him, what he eats, what his blood sugars and blood pressure and pulse are, what he drinks, how he's feeling.
Have him do these things for a steady period of time before seeing a doctor. Encourage him to be thorough. A doctor (or your cousin) may be able to see a pattern, but even if they can't, it will provide a good picture to a doctor about what your cousin is experiencing.
A journal is a great tool for someone who is unsure about a health issue. It has to be specific though.
That way when he sees a doctor he won't waste any time.