Christina Mauser, who died in crash with Kobe Bryant, would've celebrated her daughter's 4th birthday next week

A coach who died alongside Kobe Bryant and seven others in a helicopter crash on Sunday left behind three kids — one who is celebrating her fourth birthday next week. Christina Mauser's husband, Matt, opened up about his wife missing their daughter's birthday in an interview with Anderson Cooper on Tuesday night.

When Cooper asked Mauser how he told his 3-year-old, 9-year-old and 11-year-old about their mother's passing, Mauser said "They're doing okay. My little one, her birthday is next week — that's the hard part."

"She's going to be four," he said through tears. "Her birthday's on the fourth. So, I'm trying to navigate that." Mauser said his youngest daughter used to call for mom — now she doesn't do that anymore.

"And now I walk in, she doesn't call for her... I think she gets it, she knows we're grieving. She says 'don't cry,'" he said.

Mauser also opened up about how his wife's passing is affecting his other children, saying his son is very sensitive and has been having "outbursts," so Mauser lets him get his anger out by hitting a pillow.

"I hold him and I hug him and I kiss him," Mauser said. "I give him a hug for mom and a hug for me... I just cope, day-by-day."

Mauser added that his 11-year-old daughter, who played on one of Kobe's Mamba's teams, has been relying on her friends to cope. "Kobe absolutely loved my daughter, they had a secret handshake," he said.

Mauser also said he's been experiencing a "rollercoaster ride" of emotions himself. "I'm up, I'm down. I cry for no reason whatsoever." He told Cooper he hadn't slept for two days and when he woke up that morning, he thought he was okay — then started crying again.

"I'm trying to be open to not judging myself for hurting," Mauser said, adding it helps to grieve with other people.

Nine people died in the helicopter crash, including Kobe and Gigi Bryant. Mauser not only coached Kobe's Mamba Academy team, which his Gigi was on, but also coached at Harbor Day School in Newport Beach, where Gigi attended school.

John Altobelli, the head baseball coach at Orange Coast College in Costa Mesa, his wife Keri and their daughter Alyssa, Sarah Chester and her middle school aged daughter Payton and pilot Ara Zobayan, also died in the crash.

In a phone interview with "Today Show" on Monday, Mauser spoke about his and his wife's relationship with Kobe, saying the NBA great hired his wife as assistant coach because "he saw what an amazing mind she had for basketball."

In:
• Kobe Bryant
• Helicopter Crash