Hi @elderberrysmell sorry that you find yourself here. Reading your posts, I really feel for you. You have so much on your plate.
People who are neurodivergent generally respond better to a slower, gentler approach. You should ask that the clinic follows the PEACE pathway, I.e. recognising and acknowledging his autism.
While you wait for treatment to start, I would recommend reading the book ‘skills based caring for a loved one with an eating disorder’ by Janet Treasure et al. Any psycho education that you do will help you to understand eating disorders better and to be able to cope better with challenging situations.
Check out the Charlie Waller trust for upcoming workshops. Also BEAT and FEAST-ed.
As your son is older, you may be less involved but if he wants you to advocate for him then you should be able to do that if he gives them permission.
With autism there can also be a PDA profile, a Pervasive Drive for Autonomy. In this case, it is really important that you don’t use a punitive/reward system. If there is something that he really enjoys and really wants to do but which the eating disorder is impacting, then you could say something like - I know that you really want to do X, I really want you to do X too, what can I do to help you achieve that goal?
The book will give lots of tips on communication but you are aiming to listen and validate your son, particularly as he may struggle with feelings. Things like -
I know how hard this is for you.
Thank you for telling me this.
This must be so scary etc
Treatment is the same for all eating disorders so it is likely that the first steps will be a meal plan so it might be worth discussing this with him in advance so that he knows what to expect. The unit may also have some resources in the form of a booklet with photographs explaining what will happen, which would also potentially alleviate some of the stress around the admission.
The most important thing, as somebody said earlier is to remain calm. Our unit says to be curious, not furious.
Wishing you all the best. It is a very long road but worth it in the end. There is lots of advice on here so please do ask again or share your frustrations if that helps.