A son told his dad he would "batter him senseless" before knocking him unconscious and telling cops his father should be "lethally injected".
Derrion Adams, 27, launched the vicious attack after his dad suggested to him that he should get help with his mental health problems.
Adams, of no fixed address, was in the car with his dad as the pair were on their way to get some food when the comment was aired.
The defendant then became threatening and said to his dad "wait until after, I'm going to batter you senseless".
They both went home, picking up beer and cigarettes on the way, Mr Omar Majid, prosecuting, told Wolverhampton Crown Court.
At home during the incident on January 3, Adams started to beat up his dad, kicking and punching him, BirminghamLive reports.
The victim believed his son had put a strong painkiller in his coffee as his speech began to "slur" and his vision was "altered".
The victim then went outside to call the police as he was afraid he was "in real danger".
A second attack was then caught on CCTV, as Adams kicked and punched his dad outside.
The victim says he lost consciousness during the attack.
"Apart from curling up and trying to cover himself, there was no response at all from his father," Mr Majid told the court.
"His father starts to get up, defendant comes back and punches him in the face."
The victim then left to try and get help before driving himself to hospital.
He said his son suffers from significant mental health issues and believes his son will "ultimately kill him".
In a victim impact statement, the defendant's father said: "I'm slowly coming to terms with what happened. I hope he can get the support he requires to get his life back on track."
When interviewed, the defendant blamed his dad for provoking him, telling police that his father should be "lethally injected".
Judge Jonathan Gosling said: "The defendant has been alcohol dependent for many years. He has always had a difficult relationship with his father.
"The defendant tells me his father was drunk, if that's right he may be only more vulnerable.
"I completely reject the defendant's explanation about his father being at fault."
Adams pleaded guilty to assault occasioning actual bodily harm.
Judge Gosling handed him a sentence of 16 months in prison, of which he will serve half, along with a restraining order for five years.
Adams was also told to pay a £156 court fee.
