We use the words widow, widower, and orphan, but there is no word in our vocabulary that identifies the bereaved parent.
So I’ve coined the term willower.
will·ow·er (wĭlʹō-ər) noun
a. A bereaved parent. b. A person whose child, or children, has died. c. A person that willows, or grieves the death of their child, or children: Each willower processes grief in his or her own way, in his or her own time.
[From the words willow, a weeping tree that has come to symbolize deep mourning, and power, the strength of will to carry on—despite loss.]