As a relative of a person with a diagnosis, or suspected diagnosis, of an Autistic Spectrum Disorder or ADD / ADHD, you may want to arrange a consultation for that person.
You will probably have discussed issues of consent and confidentiality with professionals in health services and/or at school. Those considerations also apply to obtaining an independent opinion, but in many cases it should be possible to proceed. If your relative lacks "capacity to consent", which may be the case with learning disability or mental health problems, then the issue becomes one of "best interests". There is usually a presumption that obtaining an independent opinion is in any person's best interests.
Owing to the partly inherited nature of Autistic Spectrum Disorders and ADD / ADHD, you may wish to explore issues of diagnosis for yourself as well as your relative, but I would be careful to proceed with this only at your request.
