I think catlover's advice is solid -- if the girls' therapist is willing to testify (usually it can be done in writing) that the girls report him saying this, yeah, a court would/should look very severely at that.
And I'm so angry I can barely type. He's proven he doesn't give a rat's ass about you, but to torment his children in this way? Un. Effing. Acceptable. (You should hear the ****** words I'm saying in my mind.)