Hi there Lye,
I’m sorry to hear that you and your brother have had such a frustrating and difficult time. I’m one of the Mencap information and advice officers and from time to time we do hear from people who have to support their vulnerable family members who have a learning disability and are going through the criminal justice system, so you are definitely not alone.
Access to justice and the removal of barriers for vulnerable people in the justice system is a major concern. Research over the past decade shows that trials involving vulnerable witnesses and suspects need to be approached in an appropriate and effective way by all parties, the courts, and the judiciary.
You may be interested in The Advocate’s Gateway: http://www.theadvocatesgateway.org/
They provide free access to practical, evidence based guidance on vulnerable witnesses and defendants. There are resources, toolkits and case examples on their website.
There is an easy read booklet about what happens when you have been arrested on this link: http://library.college.police.uk/docs/APPREF/HC-Easy-read.pdf
When a vulnerable person is detained or interviewed by the police they are entitled to an ‘appropriate adult’ whose role is to safeguard their welfare and rights.
There is more information on the National Appropriate Adults Network: http://www.appropriateadult.org.uk/
I hope this information is helpful,