Grandfather tears up after hearing his granddaughter sing a song he wrote in the ’80s

A man got the best Christmas present ever when his granddaughter recorded a song he wrote.

Mike Brooks had a secret dream. Back in the 80s, he'd wanted to join the Army and fight for his country.

A football injury and hearing loss killed that dream, but he was inspired by a Vietnam veteran's story to write a song. Decades later, his granddaughter Karli Willett did something extraordinary that changed his life.

A SONG THAT BECAME A FAMILY TRADITION

Brook would often play the song to his daughter, and his granddaughter Karli inherited his love for music and songwriting.

One day, Karli found the lyrics to Brook's song and decided to give him a very special Christmas present.

MAKING GRANDFATHER'S DREAM COME TRUE

Karli wrote the arrangements to his grandfather's song. The young woman, who is a talented singer and musician, recorded the song for Brook as a surprise gift. Then she planned the special moment she would present it to him.

MOVED TO TEARS BY HIS GRANDDAUGHTER'S VOICE

On Christmas Eve, Karli told Brook she had a surprise for him and asked her sister to hit the "play" button on the family's music center. Brook, who was seated on a couch, gasped when he realized that it was Karli's voice singing his song, and tears filled his eyes.

A FAMILY UNITED BY A SONG

Brook can be seen manfully fighting back his tears, and losing. After decades, his song, his tribute to America's brave Vietnam veterans was recorded.

When the song ended he embraced his daughter and his granddaughter with tears in his eyes. Thanks to Karli, her grandfather's song has gone viral and has been heard by over 2 million people around the world.

JOHNNY CASH'S GRANDSON SINGS JUST LIKE HIM

It looks as if the apple didn't fall too far from the country music tree. Legend Johnny Cash's grandson Thomas Gabriel has shown that he has a voice to equal his grandfather's.

Gabriel sang one of Cash's hits, “God’s Gonna Cut You Down,” and his voice is eerily similar to the deceased country star's.

Gabriel has come a long way to take up his grandfather's work. He spent 10 years in prison on drug-related charges, but he is turning his life around. He's singing his heart out, and Johnny Cash's fans are clamoring for more.