Final answer:
A housing counselor should advise the client to file a complaint with a fair housing agency or HUD to address past housing discrimination and help prevent it for others.
Step-by-step explanation:
The best advice that a housing counselor can offer to a client who experienced housing discrimination 18 months prior is to advise the client to file a complaint with a fair housing agency or the U.S. Department of Housing and Urban Development (HUD). Even if some time has passed since the incident, filing a complaint can help bring attention to discriminatory practices and potentially prevent similar situations for others in the future. HUD and fair housing agencies are tasked with investigating complaints of housing discrimination, and they can take action to enforce fair housing laws. This approach enables the client to seek redress and contribute to the broader effort of combatting housing discrimination which without remedy, can have harmful impacts such as limiting access to communities with good schools, as emphasized by former HUD Secretary Shaun Donovan.