In recent years, however, Memorial Day ceremonies outside the structure have underscored its fundamental purpose. “All of a sudden, people in the community realized, ‘Wow, this is a memorial,’” said Toba Potosky, president of the nonprofit Cadman Park Conservancy.

The conservancy and the New York City Parks and Recreation Department hope to reopen the main hall of the Brooklyn War Memorial while there are still World War II veterans alive.

“It becomes more of a debt, as the years go by, to honor what they’ve done,” said Stephen A. Varone, president of Rand Engineering and Architecture, which is surveying the structure’s condition for the conservancy. The building — now reached by steps — must be made accessible to wheelchairs, a process that includes the construction of a ramp, the installation of an elevator and the alteration of bathrooms.

Money is in hand to begin that work, said Martin Maher, chief of staff in the Brooklyn parks office: $3.5 million from the federal government as compensation for using part of Cadman Plaza as a construction staging area; $1 million allocated by Eric L. Adams, the Brooklyn borough president; and $500,000 allocated by State Assemblywoman Jo Anne Simon.

“Five million dollars gets us what we need to get people inside,” Mr. Maher said.

Over the years, the hall was used by the Heights Opera Company, the Marionette Theater Company and the Creative Artists Public Service Program, which held a competition in 1971 that gave “the place the look of a gallery that has been in a collision with a rummage sale,” as The New York Times described it.