That sounds very fishy to me: no help until K, and an immediate IEP at that point? Yes, preschool special ed services are expensive, but they are legally mandated for kids who need them. Your district is evading its responsibility.
If he has deficits in any area covered by your state's education standards for preschool (which usually include things like social communication), the district is probably obligated to provide remedial services.
Does your state have a free Legal Rights Service that helps defend people with disabilities? Or is there an educational advocate in your area? I'd be inclined to make some phone calls and get some support in getting your district to do its job. Early intervention isn't the only thing, but it matters.
