What Causes Muscle Twitching?

hi, my hubby is diabetic ( levels are currantly around 25 on medication) and im wondering if his constant twitching while asleep may be related? he is a 27yr old interstate truck driver, over weight and often over tired. he falls asleep within minutes of going to bed and wakes up rested but while asleep his wrists costantly move and he thrashes his legs - almost like hes still driving. when his sugar levels go higher he also talks and argues alot in his sleep....... any thoughts???