Can blood sugar problems cause migraines and excessive sweating?

My husband was just diagnosed with pre - diabetes. His doctor said he needs to lose 100 lbs. He has a long history of migraines, but had been doing a bit better (down to just one or two a week from about 4 or 5 per week).  Now he has had a migraine and the sweats for 5 days now and barely has been out of bed for 5 days.  He has virtually no appetite, plus with sleeping nearly round the clock, I know this can't be good for his blood sugar.  He has missed three days of work already this week.  Can diabetes (or pre-diabetes, even) cause migraines?  And can the blood sugar changes cause all this sweating?  He seems to get really hot really easily, esp. at night, and has had even more sweating streaks the last 5 days with this bad migraine.