After twenty-five years of parenting a severely Autistic child, I've found that the "experts" don't know nearly as much as they think they do. Trust your instincts and refuse any program or treatment that seems inappropriate for your child.
Sadly, a diagnosis isn't a cure. Since your son is very young, I suggest you seek extensive medical evaluations to rule out a treatable organic cause for his developmental delay. Some children have had profound reactions to food allergies; others have a physical inability to absorb certain crucial nutrients. There are countless physical problems that can interfere with normal development. Talk to your pediatrician about what testing would be appropriate.
Good luck to you