But Chyna Thomas was killed in a one-car crash in Federal Way, Wash., early on the morning of April 15. Isaiah was pulled off the court after practice that day and told by teammate Avery Bradley what had happened, and he has not been the same since. He said he will never be the same.

CHICAGO — Celtics point guard Isaiah Thomas’s younger sister, Chyna Thomas, was going to turn 23 on May 2, and she was planning to come to Boston to celebrate. She could not wait to spend time with her brother, and there likely would be playoff games to watch, too.


He has played valiantly in all five games of this first-round playoff series against the Bulls, yet he has stated that mentally and emotionally, he is still “not here.” His mind and his heart remain with his sister.

After the Celtics and Bulls play Game 6 at the United Center on Friday night, Thomas is scheduled to fly to Tacoma to attend his sister’s funeral at noon on Saturday. If the Celtics win Game 6, this series will be over. But if Chicago wins, Game 7 will be played in Boston at 1 p.m. on Sunday.

This will be Thomas’s second trip home since his sister’s death. He traveled there for two days after Game 2 so he could grieve with family and friends. Celtics coach Brad Stevens said on Thursday he has once again told Thomas he should stay home in Tacoma for as long as he needs.

“The support has been amazing,” Thomas’s close friend, Alonzo Weatherby, said by phone on Thursday. “It’s meant the world for Brad to tell Isaiah he has as much time as he wants. Basically, don’t come back until you’re ready to. This is family before anything, and that means the world.”


Still, Weatherby said, it is clear that the basketball court is Thomas’s sanctuary, the place he goes to clear his mind and find peace. So if the Celtics lose to the Bulls on Friday, Weatherby had little doubt that Thomas would return to Boston in time for Game 7.

Even Weatherby, who has known Thomas since elementary school, was stunned by his friend’s ability to play in Game 1 of this series, just one day after his sister’s death.

“I told him I don’t know how he does it,” he said.

Nearly two weeks have passed since Chyna Thomas was killed, but the wounds remain very raw. The Celtics’ games seem like a brief escape for the Thomas family back in Washington, but really there are no escapes, Weatherby said.

“I don’t think even the game is a Band-Aid on that feeling,” he said.

Weatherby said that Isaiah and Chyna were very close. He recalled going to Thomas’s house to pick him up when they were in fifth grade, and before they left they would turn up some music so 5-year-old Chyna and Isaiah could start dancing together.

“She was cool,” Weatherby said. “She was the little sister. She wasn’t the tag-along who tried to hoop with him. She did her own thing. She didn’t try to emulate him.”

But she did support him. She attended many of Isaiah’s games at the University of Washington, and even flew to Charlotte, N.C., when the Huskies played there in the 2011 NCAA Tournament.


“She had such a bright smile,” Weatherby said. “She was the baby girl in the family. Just a really, really good kid. To me she’s always going to be a little girl, but she was a beautiful young woman. I watched that little girl grow up. It’s just tough.”

Weatherby said that Thomas and his father, James Thomas, doted over Chyna. One of his fondest recent memories of them all together was at Thomas’s wedding last August.

“It was like a humungous family reunion,” Weatherby said. “We had a blast. Everybody was smiling.”

Adam Himmelsbach can be reached at adam.himmelsbach@globe.com. Follow him on Twitter @adamhimmelsbach.