Previously, the High Court in Edinburgh was told Mr Rollinson had collapsed following the assault and never regained consciousness.
The boy had previously been reported to the police for assaulting another bus driver. A supervision order for that offence had ended three weeks before the fatal attack on Mr Rollinson.
The teenager was part of a group of youths who had been drinking heavily on the evening of the attack.
The boy and another youth had gone to the bus station to get the last bus home.
Mr Rollinson had told him he was too intoxicated to board the bus, which had upset him. Mr Rollinson switched off the bus engine and told the other passengers he would not be leaving until the boy got off the bus.
Mr Rollinson asked a colleague for help with the situation.
When they got back to the concourse, the boy pointed his phone in Mr Rollinson’s face, leading to the driver grabbing the phone.
This led to a struggle between the pair, during which the boy headbutted the driver.
The court heard that the boy had then “completely lost control”, raining punches on Mr Rollinson’s head and body, before being pulled away by another youth.
