Maddie & Simon’s connection

Now that episode 7 is out it may have finally explained how Simon is able to see Maddie in the afterlife. “Trauma is power,” and this power comes from the scars. Both Simon and Maddie were in the classroom scar when they were both in pain, emotionally and going through traumatic experiences having lost each other. This power combined with the power from the scar is what gave them the connection to see each other, just like how Mr. South briefly saw Mr. Martin in the bunker.

This is why Simon can only see Maddie at the scars, because that’s where the traumatic power is and allows them to see each other the same way they did originally. There could be more to add to this but I feel this makes sense.