Both the film's own writeup (an excerpt is below at the end of this post) and a recent review in the online edition of Variety suggest that this film aims to portray both the challenging and positive aspects of family life and experiences with a son or daughter on the autism spectrum.
From Variety's review, complete with Hollywood shorthand jargon, (read the whole article here):
"Regan primarily focuses on five children and their parents, and not the least of the pic's accomplishments is that all five kids' one-of-a-kind quirks and temperaments are fully experienced without excessive reference to medical terminology or anything extrinsic. By the time it's revealed that one of the fathers is [singer-songwriter] Stephen Stills, the information seems entirely secondary to his son's unique personality and encyclopedic knowledge of dinosaurs. With nary a throbbing violin (though one boy plays the cello), pic manifests each child's value, minimizing neither their undoubted potential nor their very real problems."
This marketing writeup below, written for a general public audience which may know little or nothing about autism spectrum disorders, comes from the film's website:
Ten years ago, autism was a relatively rare disorder, diagnosed in one in 10,000 children in the United States. A decade later, one in 150 children is diagnosed with some form of the disease. ... Autism: The Musical counters today's bleak statistics with one woman's optimistic pledge to lead a group of autistic children in defying diagnosed expectations, by writing, rehearsing and performing their own full-length musical. Following five Los Angeles children over the course of a year, director Tricia Regan captures the struggles and triumphs of their family lives and observes how this musical production gives these performers a comfort zone-often for the first time-in which they can explore their creative sides.
I've put in a request to the filmmaker to see where else the movie is scheduled to play and will report back when I hear.