His father, Andrew Thompson, is offering a $10,000 reward for information leading to the arrest of the offender.
The 21-year-old, who does not want to be named, had six teeth knocked out and needed emergency facial surgery after he was attacked in the Kingsway City Shopping Centre carpark in Madeley about 6.50am on December 28.
The high-functioning autistic man was walking through the carpark when a stolen white Ford Territory pulled up in front of him, blocking his path.
The offender got out of the SUV and punched him straight to the mouth, but did not steal anything before leaving with a woman driver.
The victim suffered a deep gash to his upper lip, but managed to get home having not lost consciousness.
Mr Thompson described an alarming scene at the Greenwood family home. ‘He was covered from head to toe in blood,’ he said.
‘The cut went all the way through to the other side ” his lip was totally split open. ‘He’s lost six teeth ” mostly on the top ” so both of his front teeth.’
Mr Thompson launched a Facebook group to find the attacker, which has had more than 60,000 views to date.
He said his son was now too concerned to leave the house on his own; unable to catch public transport to Mt Lawley’s Edith Cowan University where he studies computer science. ‘That’s why he’s hanging back this semester’