SANTA CRUZ — Jaleel Cousins has gotten used to the stares. When he goes to the grocery store or a movie, he often hears the whispers — “Is that him? That’s him, right?” — and awaits the inevitable photo or autograph request.

After almost a decade of this tired routine, Jaleel no longer minds having to tell people that he’s not four-time NBA All-Star DeMarcus Cousins, but rather his younger, much-lesser-known brother. What bothers Jaleel is when the interactions aren’t so friendly.

“The frustrating part is some people don’t care what they say,” said Jaleel, who is 6-foot-11, 255 pounds, with a black beard and strong jaw line. “They’re just rude. They’ll just come to you and be like, ‘You have a bad attitude!’ And it’s coming from someone who’s never even met my brother.”

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Jaleel, 25, can’t help but feel protective of DeMarcus. The two sons of a single mother who also has four girls, Jaleel and DeMarcus have looked out for each other since growing up in Mobile, Ala. And that’s what has made their current arrangement ideal. As a reserve center for Golden State’s G League affiliate in Santa Cruz, Jaleel is only a 90-minute drive should DeMarcus need anything.

Jaleel has been a sounding board whenever DeMarcus, who signed a one-year, $5.3 million deal with the Warriors in July, has vented about his rehab from a torn left Achilles tendon that could sideline him at least another few weeks. In return, DeMarcus has encouraged Jaleel to stick with basketball whenever doubt creeps in.

Because DeMarcus is three years older, the brothers have never played on an organized team together. Last month, when DeMarcus participated in three scrimmages in Santa Cruz as part of his rehab, he was Jaleel’s teammate for at least a few hours.

During DeMarcus’ first G League practice, he fed Jaleel for a driving dunk. Two days later, Jaleel returned the favor, hitting DeMarcus for a layup off a pick-and-roll.

“The one thing we said when we got Jaleel was, ‘Man, he can really pass,’” Santa Cruz Warriors head coach Aaron Miles said. “So now seeing DeMarcus pass, it’s like, ‘OK, they’ve both got that type of feel.’ Must be a brother thing.”

Outside of looking alike, growing up together, having similar mannerisms and boasting an innate passing ability, DeMarcus and Jaleel have little in common.

DeMarcus was a prodigy who played basketball for barely two years before Rivals.com ranked him as the top incoming 10th-grader in the country. Though Jaleel was an all-state selection his senior year at Spanish Fort High School outside Mobile, he was far from a top recruit. Only after two seasons at a junior college in Texas did he land a Division I scholarship offer, from the University of South Florida.

Late one night during his junior year with the Bulls, Jaleel was FaceTiming a friend in his SUV when a man pointed a gun in his face and shouted, “Give me everything!” The buddy who had been on FaceTime with Jaleel immediately called DeMarcus, who couldn’t get in touch with Jaleel because the thief had taken his iPhone, as well as his wallet and car.

In those tense minutes before Jaleel tracked down a phone to tell DeMarcus he was OK, DeMarcus looked into renting a private jet to fly to Tampa, Fla., and search for Jaleel. The experience was a reminder to both that family matters most.

Over the past three years, as basketball has taken them to different teams and states, Jaleel and DeMarcus tried not to go more than a couple of days without texting or calling. That was most difficult last season, when Jaleel — fresh off two disappointing stints in the G League (formerly the NBA Development League) — moved to Changhua, Taiwan, to play with the ASEAN Basketball League’s Formosa Dreamers.

His contract had promised a fully furnished apartment with wireless internet, but he arrived to find a room in a rundown, converted nursing home with no Wi-Fi and a creaky mattress. Jaleel said the coach, who had last worked for a local high school team, seemed to have minimal grasp of X’s and O’s.

After a couple of months, Jaleel returned home to Mobile and awaited the birth of his son. In late January, Jaleel was at New Orleans’ Smoothie King Center when DeMarcus tried to rebound his own missed free throw, landed hard on his left leg and, after hopping a few times, crumpled to the floor.

Nine months later, with DeMarcus in the early stages of his rehab with Golden State, Jaleel signed with Santa Cruz. DeMarcus saw his brother play for the first time in person since Jaleel’s senior year at South Florida during Santa Cruz’s home opener Nov. 7 against the Stockton Kings. In two minutes, Jaleel had no points, a block, a steal and two turnovers.

Such has been the story of Jaleel’s season. On a roster loaded with NBA prospects, he has struggled to earn playing time. His 5.4 minutes per game are less than half of what he averaged with the G League’s Reno Bighorns and Texas Legends last season.

At times, Jaleel has contemplated moving on from basketball to try something else. The goal of playing an NBA game against, or alongside, his big brother has kept him going.

“He’s a hard worker,” DeMarcus said. “He doesn’t give up. We’re brothers for a reason. We’ve got a lot of similar traits. Extremely stubborn when it comes to overcoming things, adversity or whatever the case may be.”

Added Jaleel: “I just want to make a name for myself. ... I get called ‘DeMarcus’ a lot, and I just want to make my own name so that it’ll be ‘DeMarcus and Jaleel,’ instead of just ‘DeMarcus.’”

Connor Letourneau is a San Francisco Chronicle staff writer. Email: cletourneau@sfchronicle.com Twitter: @Con_Chron