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David MacNeil, the CEO who spent millions on a Super Bowl ad with his dog Scout, says he hopes the pricey spot will save lives instead of just sell products.

After Scout collapsed from an uncommon heart tumor last summer, MacNeil was given heartbreaking news. The golden retriever was diagnosed with cancer, and veterinarians at the University of Wisconsin said he had only a month to live. MacNeil, not ready to say goodbye, rejected the prognosis.

Scout is now on his way to being cancer free, and to thank the vets who saved him, MacNeil got them an unconventional gift: a $6 million spot during this Sunday's Super Bowl.

MacNeil, CEO of the car accessories company WeatherTech, was so grateful that he felt a donation alone wasn't enough.

"There's so many companies selling this snack or this beer, that car or truck or whatever," MacNeil told "NBC Nightly News." "I'm like, 'What can I do that's a really good thing to do to help the university and the school and animals?'"

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MacNeil was on a business trip in France when he got the call that Scout, 7, had collapsed and needed to be put to sleep. He immediately got on a plane and flew back to Wisconsin to be by his dog's side.

"I land. Five minutes later I'm at the vet hospital. He's sitting there in the corner wagging his tail going: 'Hey, Dad, great to see you. I'm tired of this place. Let's go home,'" MacNeil said. "And I'm like: 'I'm not putting that dog down. There's absolutely no way.'"

Six weeks of chemotherapy, radiation and immunotherapy later, the tumor had shrunk by 78 percent. Two weeks later, it was down by 50 percent more.

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Mackenzie Pellin, a veterinary oncologist at the University of Wisconsin, was part of the team that treated Scout. She recalled how calm and resilient Scout was during his operations and treatment.

"He is a very good boy. He is so calm. He loves everyone. He loves every dog he meets," she said.

Pellin said the Super Bowl ad, which encourages people to donate to the veterinary school's research, will help her team conduct more research and help more animals.

"While the kind of magnitude of Scout's story that we can tell it with a Super Bowl commercial is unique, certainly the connection that he has with his owner — that love between an owner and their dog — is not unique," she said.

Scout is still battling small tumors in his lungs, but MacNeil plans to continue fighting, and Pellin said Scout is responding well.

MacNeil said: "He's amazingly important. He's a regular, solid member of our family."