BOSTON (CBS) — While he looks like his usual self on the floor, Isaiah Thomas has been anything but himself off of it.

Thomas is still mourning the loss of his younger sister, Chyna, who was killed in a car accident in Washington on April 15, just one day before the Celtics’ first-round playoff series against the Chicago Bulls began. Some missed free throws aside, Thomas has pretty much been everything he was during the regular season, leading the way for Boston with 25.5 points over the first four games of the series.

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He had that patented IT hop in his step on Sunday night (Bulls head coach Fred Hoiberg has a different description of it), pouring in 33 points in Boston’s Game 4 win in Chicago to even the series up at 2-2. Thomas spoke with reporters for the first time during the series after Sunday’s victory, discussing the loss of his sister and the emotional boost his teammates and the Celtics organization has provided him during this tough time.

“Mentally and emotionally, I’m not here, so I just feed off what the guys give me,” Thomas told reporters. “They give me a lot of confidence. I can’t do it without those guys. They believe in me.

“Being here is what makes me, I guess, sane. It makes me feel somewhat normal through these tough times,” he said.

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Thomas returned home to Tacoma, Washington between Games 2 and 3, when the series shifted from Boston to Chicago. He joined his teammates just ahead of Friday night’s Game 3, scoring 20 points in the Boston win. Celtics head coach Brad Stevens is still stunned that Thomas has played in all four of Boston’s playoff games since the death of his sister.

“I can’t believe it,” Stevens said. “I tried to say that earlier this week. But what he’s been through and the day-to-day, it’s been unfathomable the way that he’s performed on the court. It’s been really incredible. And it didn’t go our way in Boston, but the guys were resilient enough to come back and tie this up. But we have a long way to go. But what he has done has been remarkable.”

“They’ve been everything,” Thomas said of the Celtics. “This organization is the best organization there is, from the people who work in the [TD] Garden to the players, the coaches, everybody who is a part of the Celtics. They’ve been supportive. The whole world has, really, so I can’t say enough about that.”

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