Corkman David Keohane, with his father Tom and sister Carol by his bedside, pictured in hospital in Sydney in the aftermath of the August 2008 attack that left him in a coma.

The family of David Keohane have expressed their disappointment at the not guilty verdict handed down to their son’s attacker yesterday in a Sydney court, with David’s father Tom saying that he hoped the accused man, Thomas Isaako, would “rot in f**king hell”.

A jury found Isaako not guilty of attempted murder for an attack which left the 29-year-old Corkman in a coma for seven months. He pleaded guilty to the lesser charges of robbery in company and inflicting grievous bodily harm and will be sentenced on April 21.

”I feel that it is my son who has been given a life sentence,” Tom Keohane said outside the court. “I just hope that when judgment comes [on the two lesser charges] that the judge comes down hard.”

Mr Issako admitted to his part in the attack that left Mr Keohane with serious head and facial injuries, but  denied that he ever intended to murder him.

The case against Isaako, 21, began on Monday March 8 in NSW District Court in Sydney, when the accused pleaded not guilty to attempted murder but guilty to robbery in company and inflicting grievous bodily harm.

On day three of the trial, the court heard from doctors who treated Mr Keohane in the aftermath of the attack, which took place on August 9 in the beach side Sydney suburb of Coogee.

The court heard how the head injuries suffered by Mr Keohane in the attack were so bad that they were “akin to someone who is deceased” adding that Mr Keohane had been “lucky to survive”.

Dr Vanessa Sammons, the neurosurgeon registrar who treated Mr Keohane, said his prognosis had been “very, very poor”. She also spoke of how she recalled looking at the CT scan and thinking ‘‘what could possibly have caused that extent of damage’’.

“To have the degree and number of fractures that David had I cannot imagine that what happened was one or two blows,’’ she told the court. “It must have been multiple and from multiple directions.’’

Dr Sammons also recalled conversations at the hospital when doctors agreed his prognosis was extremely poor and “we thought he would do very poorly and he would be lucky to survive”.

“In my first conversation with David’s family, I said he could possibly live but he would never be the person he was,” she added.

Mr Keohane woke from his coma at Cork University Hospital in March 2009, and is said to be on the road to recovery.