Who Is Responsible for the Actions of the WeakMinded Hypnotized or Paranoid

A was sitting on a park bench. A was of a nervous disposition. A saw three youths walking towards him. One of the youths was swinging a bicycle chain in his hand. A was apprehensive that they were going to attack him. A stood up and started to walk away. The youths followed. A turned around and shouted: ‘one step further and I’ll defend myself’. The youths believed they were being threatened and one ran away. The second youth was unable to run because he had heart illness. His brother, the third youth, stayed with him. The second youth, who by now was feeling very unwell, stumbled forward and fell on A. A believed that he was being attacked and kicked the second youth-inducing a heart attack. The third youth entered the melee to protect his brother and punched A in the face before a passer-by stopped the melee. The youths had not intended to attack A but had been walking through the park to retrieve a broken bicycle.
Advise as to any criminal liability. Cite appropriate cases and/or authorities in support as necessary. Lukas, a 14-year-old, was playing next to a main busy road. He threw stones at passing traffic. Sheila who was driving her car on the main road was struck by one of the stones causing the car to crash. Sheila suffered back and neck injuries. Lukas also threw another stone at Jack’s lorry as it drove past but the stone missed Jack and instead hit Andy’s van, smashing the windscreen and causing Andy facial scratches and several cuts to his hands. Lukas was arrested and during the police interview, it appeared that Lukas was of low intelligence and had not realized the dangers of throwing stones.
Advise as to any criminal liability. Cite appropriate cases and/or authorities in support as necessary.