That is a tough situation, for sure. It sounds like the classic "golden handcuffs" to me.
Have you spoken to an attorney about your state's spousal support, child support and property laws? It is possible that your husband could be ordered to support you while you get on your own feet financially.
I certainly don't know the extent of your sons' disabilities or why you choose to homeschool, but it sounds like that decision is keeping you attached to a moody, abusive alcoholic, so it would be worth investigating your children's educational opportunities with an eye toward freeing yourself from your husband and his threats of ruination.
Because they are almost certainly being harmed by your continued relationship with their dad.
Please talk to an attorney. I don't know how you can adequately evaluate your situation without knowing the FACTS of what leaving would mean for you and your children.