At the top of the
autism post at this site, there are several links, a couple from moms who have ended (or reduced) their autistic child's "symptoms" through diet (gaps diet), the use of clay products, etc.
That being said, our own "active" kids, four in a row, went to daily Mass for the most part, and usually we ended up in the vestibule. It was a big enough area for them to move about, if they needed to.
When my brother-in-law became a priest, his motto was, "[g]et rid of the cry rooms; bring forth the children." He's been a priest/pastor for 20+ years. Autistic children would be welcomed at his parish, is my guess.
Good luck to the mother of this post. She's on a crusade; I hope she wins!