Hey, I am also looking to what types of questions will be on the mid term. I think a good place to maybe start would be the discussion questions he posts every lecture... they seem to test our knowledge on important aspects from each lecture. Also maybe some defintions or concepts, like what is medical geography and why is it important to understand?, or maybe explain demographic transition models, maybe causes of death, why are some deaths increased in developing nations, what do we die from...
Hope it helps!