OMG! I am so sorry this happened to your family! It was the steroids, not the Humaworm. The steroids will cause extreme migration of the larvae. The steroids do not kill(there is nothing in a steroid to kill parasites), they simply stop all inflammation which allow the larvae to overwhelm. The damage was already done. This link is to the CDC's page about hyperinfection.
You can contact me at firstname.lastname@example.org if there is anything I can do to help. These cases usually need extreme doses of Albendazole then Ivermectin along with many, many stool samples. It is very rare, but can be treated and it needs the two aforementioned medications. A good infectious disease or tropical disease doctor can help.
Hyperinfection syndrome and disseminated strongyloidiasis
Hyperinfection syndrome and disseminated strongyloidiasis are most frequently associated with subclinical infection in patients receiving high-dose corticosteroids for the treatment of asthma or chronic obstructive pulmonary disease (COPD) exacerbations. Subsequent impaired host immunity leads to accelerated autoinfection and an overwhelming number of migrating larvae. Whereas in chronic strongyloidiasis and in hyperinfection syndrome the larvae are limited to the GI tract and the lungs, in disseminated strongyloidiasis the larvae invade numerous organs.