Travelling to America with AS

[unfitmother]

We're taking the dcs to America this year, New York, then Orlando.
DS, who has AS, can't queue to save himself we managed a day in a theme park once before just using 'fast passes' I am aware that there are systems in place for people with SN but how does one qualify and what 'proof' do you need of a SN?

docs letter, statment should do but if you make it known to the airline they may be able to help a lot eisier then if you wait tell you ready to board