7-year-old boy battling brain cancer makes Valentine's Day card for doctor's secretary, whom he adores

Michael Uyaguari flashes a grin that's shy a few front teeth, as he chants: "MRI. MRI. MRI."
He isn't quite sure what he's saying. But at 7, he's no stranger to those letters.
Michael has an inoperable brain tumor.
It's not cancerous, and ...