It would only be a problem if his understanding of the world were unaccompanied by empathy. Those aspects don't seem asynchronous at all. During times when his senses are overloaded, he'll need safety. His sensitivity will prevent him from wrecking the place, but without hugs and similar havens, perhaps you can work out something with him other than the thumb? Even at the other end of a life, there will be many things that move those who see and feel clearer.
Be grateful that he finds company with the older children and adults now, it will not always be so. However, he'll learn quite quickly to behave as you may wish, mainly because the world will teach him that.
If you were him, would you like to be 'normal'? Would you like your family to cherish and encourage you as you are, or help you become 'normal'? We were fortunate to have several children, so perhaps they are comfortable being 'odd' together, and not having to explain their oddities. They have a few friends they'll probably keep all their lives, and many peers they could hang out with, but hardly ever do. Interestingly they developed a handy currency of being able to enter and resolve tribal issues within and across different 'friendship groups' as teenagers. Despite, or possibly, because they belong to none, but are welcome at all. I can only imagine it took a lot of standing their ground, but at no point have mine ever said they wished they were other than they are.