Dayv e-mailed me scans of paperwork that document his diagnosis and the personnel treating him. The letterhead contains the oncologist's office name and address. I looked up the oncologist, his medical office, and the other treating physicians online; all are real. However, I can't confirm that Dayv is a patient with the doctor's office because they aren't allowed to give out that information.
Dayv has asked me to keep the documents private. Short of hiring a forensic expert who specializes in digital imaging, there's nothing else I can do to verify his claims.
Whether this information satisfies you or not is a personal decision, and whether you choose to make a donation or not is up to you. At this point, you either believe him or you don't.