Eighteen-year-old Scott Johnston, from Earlston, was the front seat passenger in the Mitsubishi involved in a collision that happened on the A697, on Sunday, January 1, around 7.10pm.
According to police, the car was travelling west on the road when it crossed the opposite carriageway and struck a tree.
The driver of the vehicle, who is aged 17 and named locally as Bobby Thornton, was taken to the Western General Hospital in Edinburgh, where he was said to remain in a critical condition.
Police are appealing to anyone who witnessed the collision, which happened just west of the junction with the B6456 road for Westruther, to contact Lothian and Borders Police on 0131 311 3131.
* Local football team Earlston Rhymers announced on their website that they have postponed this weekend's planned match with Lauder as a mark of respect.