Casey recently shot his father Danny as an armed robbery attempt went horribly wrong, and the violent criminal later passed away in hospital as a result of the incident.
In episodes soon to air in Australia, Casey finally heads to court with the knowledge that he could be facing a long prison sentence.
Younes told TV Week: "He's very scared and he knows that if the trial doesn't go well, he'll end up in jail. He's already experienced juvie and had a pretty horrible time in there, so he's worried that it will be worse in a real prison.
"He's expecting the worst, with a small hope that something good will happen to him."
Unfortunately for Casey, he finds it difficult to provide a clear account of the impossible situation he found himself in on the day of the shooting.
Younes explained: "The lawyer is questioning why he made a fatal shot at Danny rather than just a shot to the foot. Why did he shoot him in a place where he would die?
"All these questions are being raised - and Casey doesn't have the answers."
Confirming that Casey later suffers a panic attack in court, the actor added: "It's pretty full-on and there's not much you can do for someone suffering a panic attack."
Home and Away airs the trial scenes next week on Network Seven in Australia, and late January on Channel 5 in the UK.