When women separate from abusive men especially as the girls are teens, they will very quickly decide if they wish to see him.
His behaviour is appalling.
Privately I have zero doubt your girls think your husband is a prick.
The older they get the stronger that realisation will be.
OP, you are trying to negotiate with a house terrorist.
You don't negotiate with terrorists.
What you should be doing, if you genuinely care about your children is seriously look into how separation would look.
You call Women's Aid and talk to them about what is occurring in your home.
Check out housing and finances
Really look into it.
THEN tell your hisband what you have done.
You tell him he is abusive and an ABUSER.
That you are looking to seperate as the environment is utterly toxic and you will no longer try and persuade him to change.
That he will be able to see the children if they want to but because of HIS behaviour and abuse of them and the whole house, you doubt they will want to maintain contact long term.
Tell him whilst you pity him, you are done trying to help him become a decent parent to his children.
He is a terrorist in the home and his abuse has to end.
OP, how he behaves and reacts to the above will inform you hugely to who he really is.
If he sees it as the biggest wake up call of his life and decides to get himself help, then maybe he has a chance.
But if he reacts with outrage, sulking, accusations and threats, you will know that his ABUSIVE side to him is dominant and he will never change.
Make no mistake OP, as a clearly bright, educated and intelligent woman, you are complicit in this situation by allowing such a man to remain in the home.
Far better to separate and the children have a primary residence that is respecful and nurturing.
They will very quickly distance themselves from him if he behaves badly after separation.
I think far too many woman stand by and try and win round terrorising spouces instead of calling them out and getting rid.
IMO your first obligation is to your children.