If a child / teenager has PDA then one of the most basic strategies is to reduce demands. That isn't a parenting fail, it's a reasonable adaptation given his neurodevelopmental (difference/disorder/condition - delete as applicable so no-one is affended).
It is extremely common for that person to behave differently in different situations. For many, they use up all their emotional energy being 'fine at school' and have nothing left at home. They may come home in a state of extreme sensory or emotional agitation and be triggered by the most apparently minor events. The coke bottle analogy is often used - the child is the bottle being shaken constantly throughout the day and the parent is the one who unscrews the cap and the contents errupt.
It is impossible to give specific advice because every child / family situation is different. What is vital is to understand the child's difficulties. Strategies for children with PDA are different from most other presenations of ASD, and PDA parenting will look very different from 'typical' parenting.
Hanging the washing out may be a reasonable request, and he complied with the request . But that might just have got him to the end of his resources for coping. Being asked to redo it was the point at which the coke bottle exploded. I really doubt his reaction was about the washing alone.
Of course no one 'should' experience violence in the home, but a great many of us do and there is no simple solution. I have no idea where Rudgie thinks all these specialist childcare units are for children with complex ASD / PDA???
Blaming the child with the disability is as unhelpful as blaming the parent.
OP it sounds like you do not have the support that you and your family need. You are under unbearable strain and that is destroying your relationship with your DS. I feel for all of you.
In our area there is a Police scheme for people with communication difficulties including ASD. You register online and th person gets a personal number and identification card that they use in emergencies. The system will have details of their difficulties and best approaches for dealing with the individual. Its called Pegasus. Check to see if your area has the same. You could at least then alert the police system so if you needed to call them out because you or the family were at risk, they would be aware.
Contact your local NAS branch who can help get you support. Contact the social care team as well - they have a duty of care towards your DS and other children. In my experience, they will act more urgently if you have other children at risk. And I'm talking about additional home support or respite etc. not taking into care.
Is your DS under CAMHS? Speak to them or if not ask for a referral urgently from your GP.
Your son's behaviour is indicating that everything is not ok and school is likely to be part of the issue. The degree of violence at home may be evidence of the extent to which he is having to suppress his anxiety / stress at school. I would speak to school.
This may help
axia-asd.co.uk/evidence-autistic-people-hiding-masking-difficulties-educational-settings/
Have a look at this resource on Facbook. He has written some excellent pieces about children who need extreme control / high anxiety / PDA
www.facebook.com/search/top/?q=autism%20discussion%20page
I really hope you, your son and the family get the support you need