DAN HOFFMAN: Grief can break your heart. Here's how to keep it from breaking your life

Roman emperor and Stoic philosopher Marcus Aurelius once said, "If thou art pained by any external thing, it is not this thing that disturbs thee, but thy own judgment about it."

If there is one thing my sons and I learned from my late wife Kim's fight against cancer, it was how to distinguish between traumatic life events over which we have no control and the power we have to respond to them as we choose.

A few weeks ago, my sons and I watched "White Room," a short introspective film directed by JT Rees. The film tells the story of 24-year-old Reese, who has tried for years to avoid dealing with his feelings over his older sister Joy's death. But grief has a way of lingering in our hearts while gnawing away at our inner peace. The movie is about sibling love and coming to terms with the loss of Reeses older sister.

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"White Room" is based on JT's own life experience. When he was 9 years old, he lost his 12-year-old sister Jessie to brain cancer.

My sons and I never met Jessie Rees, but we have bonded deeply with her family over shared grief from losing loved ones to cancer. And for years, we've been soothing our broken hearts by partnering with the Jessie Rees Foundation to support kids in the fight for their lives against pediatric cancer.

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We were always a close-knit family, but now it was the three of us, whom my late wife Kim lovingly called "my boys," facing the post-traumatic stress Kim's fight against cancer had left in its wake. That's why we identified so profoundly with JT's alter ego and protagonist Reese when Joy showed him how to process his sorrow by understanding it was not his fault.

"I had cancer!" Joy screams. She comforts Reese and exhorts him never to give up. "It's OK to cry," Joy says. "I'll always be right here watching you. You know where to find me."

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Joy encourages Reese to "Live your life. Promise me you'll try." Grief can paralyze us. But even if we have no control over the disease that took our loved one's life, we absolutely can make our own decisions about what to do about it.

I honor Kim's memory by fulfilling the promise I made to her on her deathbed to do my best to ensure our sons live their lives to the fullest while carrying with them the grief of losing their mom to cancer when they were only 8 and 11 years old.

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And so, on the day after their mom passed away, my sons went to school just as they had throughout Kim's fight against cancer, including her last few months in hospice. They expressed their sorrow with the help of a service dog and art therapy. They went to swim practice a