Your daughter might be old enough for you to share some of the MLC information from here...especially the "script" they all seem to follow in some way, also the strange behavior...the abandonment, etc...
I know with my kids and myself, it helped to see that my H wasn't the only man in the world doing this (not that I wished this on my worst enemy, mind you)...it helped my middle daughter the most, she was closest to him, she also played the hardest with him. She refused to speak to him period, about anything, until he had fully redeemed himself in all ways with everyone, including God!...I was certain their relationship would be ruined forever but you would never know that now to see the two of them working on a project together or watching their favorite tv shows together...
I would give you H a heads up..."You chose to move out and do what you are doing so it is up to you to keep in touch or not with the goings on of this family. If you want to know it if is 'safe' for you to visit then maybe you should call first!"
I would also tell him the same thing that I would tell your daughter..."your children love you, they are very hurt and I don't want to be put in the middle...I will support them as a mother but I can't be their father, that is your job and I won't take that away nor will I dive in to fix something that I "think" needs fixing because it isn't my relationship...I will work on my own relationship with the kids and would not expect or want for you to run interference for me in that so I will give you the same respect!"...P.S. You are on your own in this one buddy!