How are they going to do that? A logline needs to give the reader a clear and concise summary of the plot up to either the midpoint or the beginning of the final act and set out a clear goal. It must be a visual goal, something we can see on screen, and you need to tell us, specifically, what that is.

We don’t need names in a logline. It adds nothing. What is very important here is that the reader understands that Michael has autism. Currently, there is nothing that states this. It is hinted at perhaps, but it’s never a good idea to let the reader assume something. Especially if it’s something as fundamental as your protagonist’s defining characteristic and the most important thing to understand about him.

We also need the inciting incident. What key event kicked this story in motion? Was it Michael’s isolation, or his sister’s discovery of it? Based on the information you’ve written below (NB/ never rely on this bit of additional text to tell us the story. If it’s that important, it should be in the logline) I would say it sounds more like the sister is the protagonist. She is possibly better placed to be the eyes the audience views the story through.

I really like the idea behind this, so I hope this helps.