I don’t have an autistic child so I don’t know the full ins and outs so forgive me if these are stupid suggestions, just trying to think outside the box as I hate to think of kids being bullied for BO.
Is there anything else that could help with the sensory overload in the shower that would make it less overpowering so the actual washing may not be so stressful?
Holding the shower head himself rather then it coming from the wall or putting it lower away from the face?
Changing the shower head to a different type?
Wearing earplugs or noise cancelling headphones to dim sound?
Closing blinds to dim light?
Using a soft cotton cot sheet instead of a towel to dry himself or air dry with just a robe on?
Changing sponge to flannel or just to a soapy hand?
Changing from soap to body wash (although that may be the wrong way to go?)
Washing pits on the in between days in the wash hand basin and pat skin dry? Or would that be too out of routine to do different things so it may be better to even do that every day whether or not a shower is taken?
Acupuncture changed my life. It does things western medicine tells us we can’t fix. Fixed my horrible menopausal symptoms in one go. I’m not suggesting it can eliminate all symptoms of all conditions or diseases but it’s good with pain. Sensitivity is like pain so if he is sensitive and can tolerate fine needles used in treatment it could decrease his sensitivity to touch and make bathing less stressful? Children and babies can have acupuncture. I think there are articles on autism and acupuncture. Might be worth considering. £60 a session where I am.