Over the past two weeks, as he solidified his spot in the Warriors’ frontcourt rotation, Kevon Looney was dogged by a singular thought: I wish Wati could see this.

Wati Majeed — the best friend of Kevon’s older brother, Kevin — died Oct. 14, two days before Golden State’s season opener, from what Majeed’s family believes were complications from a seizure. He was 28.

In the decade-plus that they knew each other, Looney had come to view Majeed as family. Seldom did Majeed miss one of Looney’s basketball games in middle school or high school. While Kevon was growing up, Majeed always visited the Looneys’ house for Thanksgiving and Christmas.

Looney credits Majeed for helping instill in him the diligence necessary to reach the NBA, which is why this season has been bittersweet. Finally, after overcoming hip issues early in his career, Looney is a valued cog on the back-to-back champions. The only problem is that one of his biggest supporters isn’t around to enjoy it with him.

“He was someone special to me,” Looney said of Majeed. “Me and my brother always just talk about keeping his name alive and always talking about him.”

Hours after he received his championship ring on opening night, Looney posted a photo gallery to Instagram with the caption, “Ring night was amazing wish my bro @magnificentwatt was here to see I know he was looking down #ripwati.” Among the pictures was one from June of Majeed, Looney and their friend Daniel Tucker posing with the Larry O’Brien trophy in their hometown of Milwaukee.

On Looney’s Adidas sneakers, written in black marker, are “R.I.P. Wati” and “Long Live Wati.” Golden State’s schedule kept him from attending Majeed’s funeral in Milwaukee, but Looney had a friend speak on his behalf at the ceremony.

“It’s still kind of rough on me,” Looney said. “He was a big fan of NBA basketball. He always wanted me to be great and do better.”

When they first met, Looney was in fourth grade and Majeed was a sophomore with Kevin at Milwaukee’s Riverside University High School. Kevin, who had just gotten his driver’s license, was in charge of taking Kevon to club games, and Majeed tagged along.

Even then, Majeed could tell that Kevon had a shot at greatness. After games, Majeed often stopped Looney on the court, giving him impassioned speeches about reaching his potential. The crux of his message — “You don’t do enough” — was the same regardless of whether Looney scored five points or 35.

While Kevon was at Hamilton High School, Majeed and Kevin put him through rigorous summer workouts at area parks. Majeed — who was no taller than 5-foot-8 and didn’t play organized basketball beyond middle school — liked to remind the 6-9 Kevon — one of the most highly touted recruits to come out of Wisconsin — that “I could’ve destroyed you in my day.”

“He was a hilarious guy, and everybody loved being around him,” Looney said. “He could always find the funny in everything. But at the same time, he was definitely somebody that motivated me, pushed me.”

Two hip surgeries limited Looney’s rookie season in 2015-16 to five games. At least twice a month, Majeed called to check on him, lightening the mood with cracks about current events or pop culture. When he wasn’t working for a truck company or handing out parking tickets, Majeed was an aspiring comedian who did some film and radio work.

Over the past year, as Looney began to earn a regular spot in Golden State’s rotation, Majeed often reminded Looney how far he had come since those summer workouts in Milwaukee. Though Majeed had long stopped daydreaming about reaching the NBA, he took pride knowing that he had served an important role in Looney’s path to the league.

Around 6 a.m. on Oct. 15, Looney awoke to a call from Kevin. Majeed, who had been dealing with seizures for about six months, died in his home and was found by his mother.

The night after learning of Majeed’s death, Looney had 10 points, 10 rebounds, two blocks and two steals in the Warriors’ season-opening win over Oklahoma City. Now, as Golden State sits atop the Western Conference standings at 8-1, Looney is the team’s top backup at both center and power forward.

“I wouldn’t be here without people like him,” said Looney, who plans to visit Majeed’s grave during the Warriors’ trip to Milwaukee in early December. “When stuff like this happens, it just makes you realize how lucky you are to be alive. … Me being in this position, I just try to appreciate that.”

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