It may be possible to confirm family relationships by comparing test results with Susan or other carriers of her ancestors' mitochondrial DNA.
Mitochondrial DNA test-takers in the direct maternal line:
Family Tree DNA mtDNA Test Full Sequence, haplogroup H1ba, FTDNA kit #658815
It is likely that these autosomal DNA test-takers will share some percentage of DNA with Susan:
Family Tree DNA Family Finder, yourDNAportal SUS1e08dea2, FTDNA kit #658815