people whose needs are primarily related to mobility (i.e. I can't walk or stand the distance or time in lines) are often suggested to use a mobility device instead. And, that makes a lot of sense - most of the walking in a day at WDW is outside of lines.
DAS often doesn't shorten the distance walked IN line and sometimes means more walks to go get a DAS Return Tme and then come back to the attraction to use it.
DAS also doesn't provide a place to sit in line.
If DAS doesn't help with the needs the person has, the CMs will suggest other things (and I promise they won't laugh). The accommodation provided by DAS is being able to wait somewhere other than in the regular line, so it may not help all need.
They don't do an inquisition before issuing DAS. They just want to know WHAT the issues are that make waiting in the regular an issue (not the diagnosis, the problems related to it.)
Just keep it short, non-medical (so plain English) and related to the wait in the line.
The people I've heard with similar issues to your child having problems getting DAS were mostly not following one of those 3.
- if it's more than just 6 sentences, it's too long. I've heard people go on for 5 minutes or more, while the CM can't ge a word in.
- if it's something you had to look up on the internet to know what it means, the CMs won't know. Also avoid alphabet soup type things (SPD, PPD, ADHD, etc)
- if it doesn't relate to something that affects waiting in line, it's not pertinent
You want to be able to complete the sentence "We would like to request DAS. My child has difficulty waiting in line because......" and possibly answer 1 or 2 simple questions.