This may sound a little strange, but it is an old, old remedy for hiccups when everything else fails.
My father got the hiccups back in 1963. He was laid up in bed at home with lung cancer. Back then there was very little that the medical field could do for what ever he had. That was a time when lung cancer was a more immediate death warrant. They actually injected my father with "mustard gas" as a possible cure.
One day he started to hiccup. The doctor tried everything, but he kept hiccuping night and day for over a week. Finally my grandmother(his mother) walked in with a jar of Quince jelly. She gave him one tablespoon full, and he quit hiccuping immediately, and they didn't come back. Two months later my father was dead.
Art