As they say around here, it's better to be right than happy. Your letter to H was "right" in all respects--but, Sweetie, an MLC man, no matter how hard he's trying to do the right thing, is not mentally able to process things as you meant him to. Even if he's receptive on one swing of the pendulum, he's going to be in 20 different emotional places on the following swings. So, if you can't make him do the right thing, or make him happy, try to work on making yourself happy. You're still totally focusing on his whims as though they were solid signposts of something. The only place you'll be able to find stability, in the end, will be in yourself.
Yes, all our children lost their innocence when one parent went into MLC. But if your D had lost it some other way--contracted childhood cancer, had a leg amputated, etc etc--what would you do? Probably, try to make life as normal as possible, and teach her to make the best of all the good left in her life, and to gain strength from accepting and growing through her pain. You would not want her to see herself as a weak victim, or treat her as one. Should you treat the current crisis any differently?