Autism in children

My 6 year old grandchild lives in Scotland and has recently been assessed for autism. At the moment evidence is being gathered to determine where on the spectrum he is. He is also being referred for assessment for ADHD and speech & language therapy through main-stream school which has SEN trained staff. I'm concerned about mood swings, bad language and other aspects of his behaviour which is challenging for everyone. I want to have a better understanding of these traits to help me support my daughter (a single parent). We have also recently discovered that he has a rare genetic condition "Microdeletion of Chromosome 15" which could be contributing to his difficulties: physically, mentally and in his relationships with others. Are there any local organisations (I live in England) I can get in touch with that might provide some information/reading materials on both genetics and management of  autism etc.?