Come September, recovering veterans in at least 20 states could be booted from a pilot program for traumatic brain injury—not because of personal medical progress, but because of the nation’s lawmakers.

Despite bipartisan support, Congress has not been able to pass an extension of the rehabilitation program. Since last fall, the extension has been attached to several pieces of veterans legislation, which failed after lawmakers were unable to agree on military and VA reforms.

“If we don’t extend it, veterans…across the country will be ejected from the care they’re going to be getting, which would constitute, in my mind, a premature discharge,” said Susan Connors, the president of the Brain Injury Association of America. “Families feel like this has been a lifeline.”

Now the VA has halted new patient admissions and informed health-care providers that it plans to discharge veterans by September 15, Connors said.

The program currently is offering more than 100 veterans the opportunity to receive treatment for traumatic brain injuries in assisted living facilities, where they get therapy for their memory, movement, speech, and community reintegration. They also relearn simple tasks, such as how to cook, make a bed, and go to the grocery store. About half of these veterans were involved in the wars in Iraq and Afghanistan, while the rest are from previous generations. Eighty-four vets already have transitioned successfully through the program.

“With traumatic brain injury, many of them are struggling to do the basics,” said Joy Ilem, deputy national legislative director of Disabled American Veterans. “The pilot [program] seemed to really offer them the type of environment that worked on a number of things they might have struggled with.”

Sens. Cory Booker (D-NJ) and Dean Heller (R-NV) recently introduced bipartisan legislation that would extend the VA program for three years at a cost of $46 million.

“The VA has indicated that preliminary outcomes from the AL-TBI pilot indicate significant positive changes in general health, activity tolerance, and social activities of veterans with moderate to severe [traumatic brain injuries]—a condition that is notoriously difficult to treat,” said a Booker aide.

More than 265,000 American troops have suffered from traumatic brain injuries, according to the Defense Department. If the agency can prove that the pilot program has produced good results, it might be expanded to other veterans, as well. But in the short term, statutory authority for the program expires September 30.

After previous attempts to extend the program failed, an extension was not included in the package of reforms that Congress is now considering to address worrisome patient backlogs at the VA, and prospects for inclusion look bleak.

“I was disappointed, obviously, that we didn’t get it in the big funding bill,” Heller said, adding that he had privately prodded Bob McDonald, the nominee to be the next VA secretary, about an extension of the program. “Around here, it doesn’t always work out the way you want it to…at the end of the day we’ll get something to happen.”

Sen. Bernie Sanders, chairman of the Senate Committee on Veterans’ Affairs, does not appear confident he can get the program extended.

“We’re working on it, but I can’t give you anything more definitive,” Sanders told The Daily Beast. “It’s going to expire in September, and we’re going to do our best to ensure that it doesn’t.”

Advocates stress that vets would suffer if the program were to expire in September.

“It would be a real disadvantage for veterans who are challenged in their recovery,” said Ilem of Disabled American Veterans. “This provides them with a program that is really tailored to their specific needs. We hope we can have the support of Congress to see this program extended.”