This may be wrong to some and I may get flamed, but you can also try wood turning on one of the lathes.
My son at that age had some eye/hand coordination problems, nothing like autism though, and what I did was to set up a 3" dia. blank on the lathe, and a 1/4" radius tool in the holder.
I set hard stops - up, down and sideways and let him create designs in the blank.
We progressed to the point where I would make up a sketch, lay out some lines on a blank and he would match the sketch.
We had a whole bunch of candle stick holders.