Is this right?
Eino's mother and your great-great grandmother were sisters.
So, Eino and your great-grandmother (or great-grandfather) were first cousins.
Eino dies at thirteen months old, so he did not have children. Since children descend from their parents, and the parents from their parents. (they make up the branches on the family tree), Eino did not have any descendants. (No branches come after his name)
Meanwhile, your great-grandparent had a child (your grand-mother) who had a child (your father or mother) who had a child (you)
You and Eino are descended from your great-great-great grandparents and their ancestors (They are the ancestors you and he have in common), but you are not descended from Eino.
My brothers and I are descended from my parents.
My brothers' children are descended from my parents;
but they are not descended from me.
(I think as their aunt, I am their 'co-lateral ancestor', along with my own aunts and uncles; but I've probably got that mixed up. Maybe, from my youngest niece's place on the tree, my parents - as their common grandparents - are the co-lateral ancestors of her and her first cousins. Genealogy confuses me.)