I'm so sorry for what brings you here but am very glad you found us.
He will choose to get help when he is ready and not one moment before. If losing his family has not done it, I don't know what else you could possibly do. And even if you were to find a way to get him to go, treatment is just a start. He still needs the desire to stop drinking to get anything out of it, and it sure sounds like he does not have that yet.
You can, however, take care of yourself and your kids as you deal with the blow your family has been dealt. You all need to know that this is not your fault--that there is nothing you could have done, said, or been to change him. Of course you want to fight for your family, and you can do that without him.
As far as fighting for your relationship, I fear that takes two.