IB...maybe it is time to also tell your kids that you don't want them in the middle either...H sending his messages through the kids, even if that was not his intention, is not good for you.
So maybe when you feel strong enough to share with D the things you are learning about her dad's "illness" MLC you could share with you that since you two are not together right now you don't need, nor do you want, to know what H is sharing with them...UNLESS it is something that she needs help dealing with and you can help her...
In other words...their relationship with their father is not your business and your relatship with him is not really their business (because if there is a reconciliation they may not be approving initially)...he is seperate to all of you and connected to each of you in one way...he is their father...he is your H...right now he is not both in a healthy way to any of you...but it is what it is and you all have to work it out in your own way for your own relationship with him...