Answer:
file a fair housing complaint with HUD and try to collect a commission.
Explanation:
Home owners that want to sell or lease property are prohibited from discriminating against tenants or future home owners on the basis of race, sex, family affiliations or other grounds.
So the homeowner not willing to to sell his home to someone with children but rather looking for someone without children is a discrimination against the new homeowner.
The broker should file a complaint with HUD and try to collect a commission for services rendered.