My best advice: watch a lotta flicks with autistic like peeps like Rain Man or I am Sam.
One of my tricks when playing was to have the PC sing childrens songs to himself during specific moments and left the players to figure out what the songs meant. For example "Ring around the rosies" was sung when they were near a place where a ritual was taking place or he's sit in his comfy chair and start singing "The Crawdad Song" ("you get a line and I'll get pole honey... Were going fishin in the Crawdad hole") when a new monster was in the area and we need to hunt it down.
I even once sang part of "he's got the whole world in his hands" to represent that we were dealing with an ancient evil threatening the planet.

There are lots of other tricks... find out what works for you and have a logic that the players will need to figure out behind your actions.