DPD Enzyme Deficiency when taking Capecitabine/Xeloda or 5-FU

My wonderful husband of 51 years died on December 12, 2018, after taking Capecitabine for only 10 days.  He was diagnosed in July of 2018 with Bile Duct Cancer, had a successful Whipple surgery and recovery, and was pronounced cancer free by his radiation oncologist (his cancer was Stage 1).  His oncologist believed that he needed a course of adjuvant chemo, and prescribed Capecitabine.  We were not aware of the early-onset symptoms of a DPD Enzyme Deficiency, critical to metabolize the chemo, and by the time the doctors recognized his symptoms in the first hospital admission, he was beyond the 96-hour window for administering the antidote, uridine triacetate (Vistogard).  He had been treated for each individual symptom (body rash, mouth blisters, diarrhea, vomiting) and not for the total systemic breakdown.  Most people are not aware of a DPD enzyme deficiency and testing should be mandatory before starting Capceitabine, Xeloda or 5-FU.  It is no longer considered a rare or unexpected occurrence.  Furthermore, oncology nurses, ER staff, and especially the oncologist need to be aware of these early-onset symptoms and start the antidote within the 96-hour window.  His death was preventable.  Our family is heartbroken.