It starts playing at the Sundance Film Festival in a few days, but in the usual vein of Sundance films it will be awhile before the average person can find it on DVD. :(
I am not exactly sure if people with AS lack a theory mind completely, I just think that their theory of mind is not always compatible with other neurotypes. Think of it the other way around, an NT trying to understand a person with AS when they have never heard of it before, the NT person is going lack a theory of mind towards the person with AS.
My 17 year old son has Asperger's Syndrome. He is incredibly smart and has the kindest heart of anyone I have ever known. But my son (ironically also named Adam) is absolutely a lost ball in high weeds when it comes to personal interaction. He even has trouble knowing how to interact with our cat. I certainly hope Mayer has done justice to people like my son and from what little of the movie I've been able to see I think he probably has.