Vickie,
Tom had terrible hiccups too. They kept him awake for nearly 48 hours, at which point I called the MO. We had been told that hiccups were a side effect of chemo (can't remember if it was from the
Erbitux or Cisplatin). The MO prescribed Thorazine and that cured them. It wasn't immediate relief; it took a bit (like a couple of hours) but it worked.
Like you, I went online to research home remedies. Did you find the homemade web sites that list hundreds of "cures" submitted by readers? If you read some of them too your dad, maybe you'll get him laughing so hard it will cure his hiccups!
Joyce