It may be possible to confirm family relationships by comparing test results with Donald or other carriers of his ancestors' Y-chromosome or mitochondrial DNA.
Y-chromosome DNA test-takers in his direct paternal line on WikiTree:
Family Tree DNA Y-DNA Test 67 markers, haplogroup I-M253, FTDNA kit #66253
Mitochondrial DNA test-takers in the direct maternal line:
Family Tree DNA mtDNA Test HVR1 and HVR2, haplogroup H, FTDNA kit #66253
It is likely that these autosomal DNA test-takers will share some percentage of DNA with Donald: