Conversation so far:
Where was Robert E.
Howard born?
Peaster, Texas.
Who were his parents?
Dr.
Isaac Mordecai Howard, and his wife, Hester Jane Ervin Howard.
Did he have any siblings?
only son.
How was his upbringing?
During Howard's youth his parents' relationship began to break down.
The Howard family had problems with money which may have been exacerbated by Isaac Howard investing in get-rich-quick schemes.
Did they split up?
Hester did not want Isaac to have anything to do with their son.

Question: When did their relationship end?
Self-contained rewrite: When did the Howard family relationship end?