For those who have been following, DH finally sent his email to BM. Of course, its been three days and she hasn't bothered to anser

BM

I see that SD14 has missed over 3 weeks in a row from school. I hope
you have made sure she has acquired the necessary homework to keep up
with her schooling. Did she see a doctor during this time and has the
school been informed accordingly? This length of absence without proper
notice can work against her future education plans.
SD17 tells me she is up to grade 11 work at school. Since she isn’t
staying there very often how do you make sure she is getting to school
when she should? Do you allow her to stay at her boyfriend’s house, or
maybe you Ex thinks it okay. She doesn’t seem to be getting much from you
in clothes either. The money I pay you has to cover that.
A week ago you dropped-off SD19's dog, Milo, at our house with no
phone call to tell us this was happening. You opened the front door,
unannounced, and put Milo into a house with no regard to our privacy or
the dogs well being. We could have been out of town, leaving the dog to
fend for himself. There could have been a dog in the house that could
have hurt Milo. We may have been out of town for 3 days and the dog may
have had no food. You had no idea of these possibilities and should never
have opened the front door without permission. Had you knocked on the
door you would have found out that someone was home
SD19 was doing well here, with a fair amount of supervision for grandson
and we were doing our best to help SD19 cope with being a mother. With
no phone call or any communication with us you decided that she would be
better off at your Ex's house. SD19 yearned for the freedom to have
friends overnight, which we didn’t allow, making her choice seemingly
easy. To accept this situation you must have known that she had a dog.
It’s is not our dog, it is SD19's dog. Do not ever come to my house
unannounced in the future if this is how you deal with your daughter’s
problems. Maybe you should learn to knock on closed doors before you
enter someone’s house.
I will require an explanation, and so does the school, whenever SD14
misses classes. I asked her 5 days ago and she refused to give me an
explanation.
If you continue to say that SD14 lives with you, please be more
responsible about getting her to school in the morning. She always got
off to school in the morning when she lived here. I am very concerned
about her school year, as a father would be.
As always, this information in this email is for you to deal with, not to
show to the kids as you have in the past.
DH

I think he did good. I, of course, would have thrown the Court Order at her, but of well. Still proud of him.