People with reflux have described their chests as feeling as though a car is sitting upon it. Lot's of people actually think they are having a heart attack where there pain is so bad. Hiatus hernia is very common in the world of reflux, some think that as much as 80% of refluxers have the hiatus hernia as well. As you father has one, I think you really should get this checked out. Slowing in heart rates have been noted by refluxers during attacks etc I also feel as though my heart skips a beat sometimes when I first lay down.
Don't worry too much about what will happen, until you have been told. Most hernias aren't treated as it isn't always necessary if the right combination of drugs is used and changes in your lifestyle are followed. My first suggestions to you would be
Don't eat for at least 2hrs before going to bed.
Sleep in an elevated position e.g. a couple of pillows as this will help gravity to keep the acid in the stomach.
Avoid caffiene, chocolate, fried foods, spicy foods, alcohol and smoking, along with avoiding as much stress as possible.
These tips alone could dramatically change your symptoms. But don't forget to see a doctor he may want to prescribe a medication etc