(CNN) Like many parents, Stephanie Northcott dreamed of the day she would get to see her son Dalton walk across the stage to receive his high school diploma.

That dream took on an urgency when she was diagnosed with a rare cancer in 2015 and given 10 months to live.

"For two years, that's all she's (been) talking about. She wanted to make it to her son's graduation," said Julie Northcott, her friend of 21 years.

The two women are as close as sisters and share the same last name because Julie is married to Stephanie's ex-husband.

Stephanie's son, Dalton Jackson, finished all his requirements and was set to graduate from Halls High School in Halls, Tennessee, on May 18.

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