Dear Shadmr,
 
Here are some thoughts:
 
If your son has a mechanical mind,  I'm thinking that he can make pictures in his head about how things work.  Could he think of bodies and biological processes just like machines?  For instance, if he can picture and discuss and understand how bridges are elevated for passing boats, could he also picture the operations of the physical body and biological processes?
 
I know that biological processes might not be as systematic as mechanical processes, but if you could build on the type of thinking he is already strong in, then use those strengths to develop his thinking in another type of subject.
 
I'm certain that he makes organized drawings of mechanical processes.  Could he also learn how to sketch biological processes in an organized fashion?  To be able to draw an organized sketch, you need to really know the subject matter.  The act of putting organized thinking on paper, will really assist his memory of it.
 
When he makes his organized sketches, he could also print labels and cues on his work, so that he's picturing images and words together.  This is also a more effective way to learn vocabulary, rather than reading and trying to memorize definitions, when there's no meaningful context for the words.
 
It's always difficult to show movement in a sketch.  Your son could draw a series of sketches to show action, just like he probably does for mechanical processes.
 
These sketches that he produces will be his study notes.  If he makes a meaningful sketch, it represents a chapter or concept, and he won't need to re-read the particular chapter or concept again.
 
These are the kinds of study and learning techniques that I've found useful when I've tutored students, whatever the subject matter or grade level.  I hope that they will be helpful for your son and his tutor.
 
Sincerely,
 
Sylvia HS
Reading Specialist
Author