Your question sort of ties into a discussion we had the last time 1841PT ran: is it the same band of PT as 1970PT?
If it is, then, yes, presumably Bramwell could be an uncle because (according to Will Loomis' Life and Death of Barnabas Collins) Barnabas had three sons, so Bramell has two (unseen) brothers, and there's always the possibilty that one or both might have children.
However, some of the facts revealed in Will's book conflict with things that we learn during 1841PT. A simple case that the writers didn't remember the history they'd already established? (These writers? No! Persish that thought!
) Or is this really a different band of PT?
It turned out to be a fun topic to debate as this storyline progressed... (hint, hint
)