Since it's past the online sign up deadline, good luck, but we've had bang-up success with the regular old Arlington swim classes for our ASD kid.
I just make sure I touch base with the instructor *after* the first lesson -- keeping it casual but keeping communication open. I say after the first lesson so the instructor can form her own opinion about how to best teach him without having a label to work with first.
Swim instructors just amaze me with their patience and kindness. Go for it.