Advice on how to get support for carers of child with severe / Level 3 autism?

Hi everyone

I help look after an 11-year old child with severe autism – with many of the characteristics of what is called Level 3 autism. So they are non-verbal, with extremely limited communication skills and not toilet trained. I am keen to get some support and advice on looking after the child but I’ve found many of the websites, books etc. on autism generally cater for more milder forms of autism. I find this particularly frustrating because generally it will be the people looking after children with severe autism who will likely need the most help.

I wondered if anyone can recommend any organisations, website, discussions boards, community groups, books that provide support to those looking after children with severe autism?

Any help would be gratefully received!

Best wishes

Iain