why tthey don't understnad "invisible disability"?

I would greatly aprpciateif if you could kindly give me some advice.

My 11 son has ASD. He still needs help for :

  • un/dressing
  • washing
  • brushing teeth
  • toileting (has not completed toilet training yet, he still need nappies)
  • communication 
  • and he is Statemented
  • and he is awared DLA with high rate of care component and low mobility

My son finds these things are very difficult due to his high level of anxiety and sensory integration problems.

A social worker came and did Carere's Assessment today, as I still have to lift him to un/dress or wash but now I have got hip joint problems and thnigns are very difficult for me to lift him.  What a disappointment it was! She told me my son "looks nornal, therefore, no help is needed from communicty care"

She insisted that he has "healthy" arms and legs and he can do maths in school so that he should be able to do all sort of things by himself and she really insisted that he is perfectly normal and should not be treated as "child with Special Needs", althought he has Statement!!!!! She also told me that one of her cliant's all joints are twisted and on the wheelchair and compare with her, my son is far more than normal.

 I am very frustrated and feels extremly sad, as people, even professioanls, can't understand his invisible difficulties (realted to ASD and mental health issues) think that mys son's difficulties are just becuase  "he is lazy" or due to "my poor parenting hence he is a spoiled kid"   Why they only can understnad and see physical side of disability? why "invisible" disability/difficulty are not equally treated as physical side of problems? It is 21st century but why (majority of ) people think "disabilty" means "on wheelchair" - for example?   

Anyone could possibly give me some comments on this issue? anyone agree with me? I am so frustrated becuase, not only my son's difficulties were acknowledged (ignored) but also his difficulties were viewed as "being lazy".