Yes most of the autistic charities are captured (Sunshine Support, National Autistic Society).
When your child needs your help you seek out help from charities, support groups etc. I've been on Facebook groups where a parents come to discuss the issue and virtually all the responses are along the lines of this:
So good they felt safe to come out to you.
Yes support them and use their pronouns.
Go to Mermaids they are brilliant.
Most autistic kids are trans so it quite normal.
I usually go on and recommended an alternative approach to affirmation which is watchful waiting. Recommend they do as much research as possible on both sides and say look at Transgender Trend, Bayswater etc. Then I get a pile as these organisation are deemed transphobic, get called names, then the admin delete my posts.
I did have a few mums DM and say thanks for the links I got them before they were deleted and this aligns with more of what I was thinking.
I praise gender non conforming kids and say that's what it is about smashing sexist gender stereotypes, but that is dismissed instead trans is the only way.
It is so hard to tackle when affirmation is just everywhere. I really hope these new centres slow everything down and truly offer a watchful waiting approach.