I'm so sorry you're having such a hard time. My friend's son is the same way. He has started taking some medication recently that has greatly improved his behavior. He only tantrums a couple of times a day now, and they are not nearly as bad.
As far as the sleeping goes, we have to give Caleb melatonin. It has helped immensely. He goes to sleep a lot more easily and usually sleeps through the night.
Good luck while your husband is away. DH is a MArine so I know how it is to be alone with the kids for extended periods. Not the most fun. Sometimes completely overwhelming. ((((HUGS))))
Bless your heart.