WASHINGTON — Jessica Swan’s daughter Mackenzie was her “miracle baby.”

She was kind, smart, and always wanted to be a scientist — even correcting her mom on the pronunciations of various dinosaurs in grade school. She grew up to be an artist and an athlete, with a love of the mountains in Alaska, where she was raised. In high school, she joined the Reserve Officer Training Corps, or ROTC, enjoying it so much that she continued with her commitment into college.

But on an Air Force cadet development trip in June 2022, Mackenzie got into a Humvee with fellow cadets. The vehicle, driven over the speed limit by someone who lacked the training to operate it, spun out and flipped. “Basically, [they] said, ‘Go have fun,’” her mother said.

Mackenzie, then 20 years old, was killed. An Air Force report issued after the accident found multiple violations of protocol. Idaho authorities filed charges against the driver, but they were dismissed in November; the case is on appeal.

“You’re living every parent’s worst nightmare,” Swan recalled in a recent interview with NBC News, with a photo of her daughter in military dress hanging on a wall over her shoulder. “And then, adding to it, immense financial strain.”

Families of active-duty service members lost in the line of duty receive death benefits, including a $100,000 “gratuity” and insurance. But family members of ROTC cadets, like Swan, aren’t eligible. Nor are families of enlistees in the Delayed Entry Program, in which individuals enter as inactive reservists and commit to report for basic training on a specified future date while being encouraged to train with their recruiters in the meantime.

For Swan, burial costs, months of missed work as a teacher, and travel between Alaska, where she lives, and Idaho, where Mackenzie was killed, drained her bank account. On the first anniversary of her daughter’s death, she packed up the house she was renting in Alaska — the last place Mackenzie called home — after being kicked out.

Having death benefits from the military “would have eliminated that financial strain because it very quickly became a logistical nightmare,” Swan said. “Support would have meant that when they put the house we were renting on the market, I could have kept it. I could have preserved the last place that she lived. Our memories in that home.”

Manny Vega has made it his business to find and reach out to families like Swan’s, knowing all too well the feeling of “screaming into the wind” for support and finding too little.

A Marine veteran from a long line of veterans himself, Vega’s 21-year-old son, Patrick, always dreamed of donning a uniform. Mere days after arriving at basic training, he got sick. Less than two weeks into boot camp, he was dead.

Vega and his family blame poor medical care and the “coldness” of military culture for a failure to get him the care he needed for complications from the common cold, saying Patrick “had been left to the care of young, inexperience, scared recruits” before his death. The Naval Criminal Investigative Services ruled Patrick’s death natural, saying he had a history of sepsis and autoimmune disease, a conclusion his family disputes.

“For me as a service-disabled veteran who carries a medal that says ‘heroism,’ to have the Marine Corps fail my son — ’cause they did, they failed my son — and to fail his family, I’m very conflicted,” Vega told NBC News. “It’s very painful. … Just the coldness of the culture was what’s really, really upsetting.”

Patrick died at boot camp, making him active duty and thus eligible for death benefits. But the questions and lessons around his death spurred Vega to channel grief into action: starting an advocacy group called Save Our Servicemembers, lobbying lawmakers for policy changes, and seeking out and supporting other families who suffered similar losses.

The old Marine motto of “don’t leave anybody behind” animates Vega’s advocacy.

“As a grieving family, you’re screaming into the wind,” Vega said. “I mean, you’re there and on Capitol Hill … you could scream at all these members and they’ll nod their head and everything, but unless you’re not screaming, but speaking and asking for specific things from the right member, it’s never gonna go anywhere.”

To ensure his advocacy went somewhere, Vega phoned a friend from his time in boot camp: Rep. Salud Carbajal, D-Calif. Carbajal, in turn, found bipartisan commonality with Rep. Michael Waltz, R-Fla., on a bill to bolster access to more military death benefits for families of ROTC cadets and delayed-entry soldiers.

Part of that bill is included in the fiscal year 2025 National Defense Authorization Act, an annual military legislative package that is considered to be must-pass. The NDAA includes their legislation that would extend benefits like death gratuity and casualty assistance to families of ROTC cadets killed in official training events. That bill passed out of committee Wednesday, with a Carbajal-sponsored amendment that would also extend Servicemember’s Group Life Insurance eligibility to third- and fourth-year ROTC cadets and delayed-entry program soldiers. More than a dozen Democrats and Republicans ultimately signed on to the amendment. The bill will next head to the House floor.

The issue is personal to Carbajal and Waltz. “He once upon a time also served in the ROTC program,” Carbajal said, pointing to Waltz. “I served in the Delayed Entry Program. We know personally what these gaps could do in terms of not providing to the families of those service members who died in the service and … what it does to their families.”

Waltz agreed, citing an ongoing recruiting and retention crisis in the military as further reason to act. The realization for families can be a shock, Waltz said: “‘Oh, wait a minute, my son or daughter is about to go jump out of planes, but they don’t get the types of benefits that every other military member does?’”

Both members agreed that policies like these can be more easily enacted when lawmakers share the experience of having served. Waltz cited a mentality of “serving a cause larger than ourselves,” and Carbajal called it a chance to “do what’s right” and put “country over parties and politics.”

As for what it would feel like to call his old friend Vega and tell him they got it done? “It’s gonna be very meaningful,” Carbajal said.

And for Swan, who’s still fighting for her daughter Mackenzie, a policy change could be a silver lining — however small.

“I’ll feel like she didn’t die in vain if it helps somebody else,” she said.