I'm confused is this author a Roosevelt descendant or not?

In My Humble Opinion
1

Re this article

How Teddy Roosevelt Diffused a Scandal by Destroying His Brother’s Marriage

The noted author William J. Mannhas the same last name as the mother of the illegimate Roosevelt son’s mother, but no where (that I can see in the article or the wiki) does he claim to be a Roosevelt descendant. Is he or isn’t he?

2

Elliott sounds like the Archetypal Presidental Brother.

3

It seems unlikely. Elliot Roosevelt Mann is recorded as having two daughters, who apparently died in obscurity, and who were unlikely to pass on the family name.