My adult daughter has abandoned her child and is with her abusive controlling boyfriend

It is time for legal authorities to get involved no one needs to get abused.

I don't think the legal authorities will do much unless the daughter is willing to report it herself and if the movies was to contact them they would only maybe talk to the boyfriend what will just make matters worse for her daughter, it's a move the daughter has to make to contact then get away from him to a safe refuge for abused woman so the can follow up come help her.

I ment if the move not movies, it wouldn't let me edit the post

Breaking of her phone is in court a offense.I was  a juror in a trial with this in part of the case the abuse was also involved.

It maybe a offence breaking her phone but without the daughters co-operation all they will do is talk to the boyfriend and without any proof of what is happening they will let him go and when he returns home will then take it out on her even more
The mother will need actual evidence she can show what's going on and to be able to talk to her daughter and convince her she needs to leave and in to a safe place, without doing that and taking it into her own hands and reporting it could lead to her daughter getting seriously beaten and hospitalised.
No case of abuse is the same and many abusers can be very smart on finding excuses on how things have happened when the law reinforcements get involved. Without the daughters co-operation it is probably not advisable for the mother to take matters into her hands.

I talked to my granddaughter today and asked had she talked to or seen her mother yet and she said she had talked to her on the phone yesterday. And your right my daughter has to get out of this situation herself, I have learned from past experience you can't make someone do anything until they want to. This isn't the first time this has happened. I just wish I knew why it is she seems to put herself in these bad relationships over n over again.I guess I just want to understand why. This is going to sound strange without you knowing all the facts...but it almost seems like she puts herself in these bad situations...like a part of her actually enjoys it. Is that possible??

What you say is right you can't force someone to do something because the more you try the more they will go against you and resent you for trying to help, I know a few people who have been in situations very simular to that not just once but several times and yes your right they do seem as though that sort of person that has control over them attracts them so to me it doesn't sound strange at all to me because it does seem to be like they need to be under someone's control
I'm not sure how old your granddaughter is but the only way I could suggest to try and get your daughter to see sense and leave is to get your granddaughter to try and appeal to her mother's good nature and tell her she misses her and wants her to come home, as you say it's your daughter that has to make the decision or she will go against everything you do or say if she feels forced by you.
I don't know what other advice I can give you but I really do hope she sees sense soon and gets out of that relationship.