Maternal and Paternal relationship is confirmed by a 23andMe test match between Guylaine Larouche and Jocelyn Larouche. Their most-recent common ancestors are Jean Larouche and Rachel Lemieux. Predicted relationship from 23andMe: sibling, based on sharing 49,7% DNA shared and 3696 cM across 21 segments.
It may be possible to confirm family relationships by comparing test results with Jocelyn or other carriers of his ancestors' Y-chromosome or mitochondrial DNA.
Y-chromosome DNA test-takers in his direct paternal line on WikiTree: