If he has no fracture or dislocation, then the injury is either compression or hyperextension. These tend to cause 'central cord syndrome' whereby the recovery is better in the legs [and bladder/bowel/sexual] than it is in the arms/hands. The cord continues to swell post operation hence the understandable pressure to 'decompress' which is not of proven benefit.
Some will make a complete or near complete recovery - this is not predictable at this stage. In the first 48 hrs or so the cord can shut down completely [spinal shock] and then there is a sequential recovery, so having no sensation in the first 1-3 days is not necessarily a sign of catastrophic injury.
Thankfully these injuries are relatively rare on a rugby pitch.
If a cord injury occurs on a pitch and is associated with a dislocation or a fracture, compressing the cord, the surgeon has less than 6 hours to decompress and stabilise the spine - i.e. the cord will 'die' if denied oxygen for 6 hours. Everytime I see the 15-30 mins spent on the pitch side i feel like I am going to have a stroke. Check the airway, put on the hard collar and get them to hospital. It takes an hour to do an MRI, probably 30 minutes to get a CT, and then there is the equipment to organise, careful intubation, and often a combined anterior and posterior operation is needed before the cord is decompressed. Anyone with a neck/spine injury and a neurological deficit that needs urgent surgery, needs to be in an operating theatre within 4 hours.