First of all, please forgive me if I haven't read all the responses yet - I will as soon as this is posted (but with current "goings on", if I don't say what is in my mind, I'll forget it).
What your friend is saying is absolute rubbish.
Let me expand... when DS was a tyke, I saw MANY markers of ASD in him, but downplayed/dismissed them and blamed myself, as I was the primary carer for a boy 4 years his senior who had ASD and I figured I must be treating the boys the same, and DS was learning from C...
It took me the better part of 3 years of DS no longer being around C, but with NT peers, to finally grasp that this was not learned behaviour, but it was who he is.
With that in mind, at 15, DS is now a self taught lightning fast typist (but does not type in the standard fashion - he has a very dominant hand, and types with all the fingers of that hand and one finger on the other) but can barely print. He uses a computer for note-taking and assignments at school, but has actually found a hobby that baffles me. He has learned to paint miniature figures. He NEVER would have submitted to "therapy", but happily sits for hours working on his models... and his fine motor skills have improved.
At 6' tall, he still looks like a sock full of soup - his muscle tone and hypermobile joints won't magically go away, but he has learned to ride a bicycle, and frequently rides to school by choice (instead of taking public transit).
All I can really say is that you are in my thoughts - there will always be those who believe they know all the answers, but have NEVER walked a step in your shoes. How you approach (or avoid) that is your own choice, but never let anyone have you believe that you are doing less than the very best for your boys.
Those who matter know differently.