A question- is this part of autism?

am have another relative with classic autism,he is a cousin,fifteen years old and lives in Dublin.

he has big problems with understanding what is real and what isnt,he imagines a lot of things in his head about real people,and has got them into trouble because to him it really did happen.
for example,he accused his dad of beating him every day to his social worker,and being social workers they took it seriously.

dad was mentioning this to one of the more autism educated staff here about Alan and how he has got his family into trouble without meaning it,and the staff said it sounds more mental health than autism.

but then again,the staff isn't that educated about autism,as dad also told him he has had a long obsession with the twin tower attacks,and the staff said that because of that, he is not autistic and is more on the mental health side, which is rubbish as classic autism can include obsessions to-more so for objects sake than informations sake,and it is needed criteria for another form of autism-aspergers,so it's hardly 'mental health',the subject shouldnt come into it as autists are not affected in the same way by things so whilst one subject may bother a non autist,it might not bother a autist.


what does everyone else think?
could not understanding that the made up memories in his head are fake be part of his experience autism or is it more on the mental health side?
his mum and dad dont know anymore than what am have wrote here,because of the lack of autism educating there.
he wasnt even diagnosed until a couple of years ago,even though he has 'obvious' autism.