Maria Bowen said she and Jamie had to visit sick relatives secretly
A mother sobbed as she told a murder trial how she found her dying son in a pool of blood after he was stabbed as he slept by her drunken husband.
Maria Bowen, 37, Llanelli, told Swansea Crown court how she was woken by 15-year-old Jamie Yeates's screams.
Carl Wayne Bowen, 42, denies murdering his stepson and the attempted murder of his wife and stepdaughter Kimberley Yeates, 19.
He also denies two alternative charges of wounding with intent.
The jury has heard that Mr Bowen admits killing his stepson but will argue a defence of diminished responsibility, telling police he was so jealous he believed it amounted to an "abnormality of mind".
Elwen Evans QC, prosecuting, has described him as "a controlling, manipulative, possessive, jealous, self-centred man".
Mrs Bowen gave evidence via a live video link on Thursday.
The court was told the defendant was so controlling Mrs Bowen had to ask permission to go food shopping.
He had forbidden his wife and stepson to see relatives who had been diagnosed with cancer but the pair had begun to do it secretly, the jury heard.
Mrs Bowen told the jury she wanted to leave her husband but she was frightened of him and what he might do.
On the evening before her son's death, Mrs Bowen said her unemployed husband had been home most of the day drinking gin and orange and smoking and had fallen asleep on the sofa.
I went up to see Jamie and he was there in a pool of blood
Mrs Bowen sobbed as she recalled hearing her son's dying screams for help.
She said she jumped out of bed and immediately.
She said: "I saw Wayne on the landing by the door with a knife and a baseball bat.
"I said 'what's wrong?' and he said 'I know what you are doing. I know what you are doing'.
"At that time Kimberley came out on to the landing and he must have dropped the baseball bat.
"He tried to head butt me but I moved back somehow so he touched me but not with any force.
"Then he tried to stab me but Kimberley and I were holding his arm. Then he turned and stabbed Kimberley in the arm."
She said as some of her seven other children came out onto the landing she pleaded with him to go downstairs and talk.
"All I said was 'let's go down and talk about this. Don't do this in front of the children.' They were behind me."
She said Mr Bowen then went downstairs, unlocked the front door and went outside carrying the knife. She followed and locked him out.
A sobbing Mrs Bowen added: "Then Kimberley said 'you had better go and see Jamie mum' so I went up to see Jamie and he was there in a pool of blood."
She then went downstairs and called the police and paramedics but he could not be revived.
The jury has previously heard how Bowen disliked Jamie so intently and would spit on his stepson from an upstairs window.