You're right about the exercise ! People who do manual work, especially in a hot climate, may have neither the energy nor need to take recreational exercise.
As for your brother-in-law, if the "blood pressure machine" is validated (www.bhsoc.org/how_to_measure_blood_pressure.stm), then it's too high, even without obvious symptoms or signs. It needs investigation and treatment IMO. Rather than "hijack" this thread, I'll post a separate one under "Health Issues".