A 17-year-old Port Jefferson High School student returned home Friday after a sudden medical emergency last month led to a diagnosis of multiple sclerosis - and more than three weeks of intensive treatment and rehabilitation.

Sean Tardif is a junior known for his accomplishments in football and track.

He woke up on Oct. 21, unable to move the right side of his body. His mother, Julie Vitrano, rushed him to Mather Hospital, where scans revealed two lesions on his brain. He was later transferred to Stony Brook Hospital, where doctors confirmed the MS diagnosis.

Tardif’s condition rapidly declined, leading to foot drop, severe weakness and difficulty walking. After continued setbacks, Vitrano pushed for plasmapheresis, a treatment that doctors say ultimately led to a dramatic improvement in her son’s mobility.

Following five rounds of plasmapheresis and ongoing physical therapy, Tardif regained strength and independence, surprising even his medical team with his speedy recovery.