What should I say or do? Best friend is really making big mistakes! Her kids are involved!?

My best friend of 15 years recently (December) told her husband she cheated on him (this was a lie) She said she wanted out of the marriage and she doesn't have feeling for him any more. Well of course her kids took it hard and especially her 11 year old. Well she has been having highs and lows and has admitted in the past that she doesn't know why she feels this way and that she wants to go out and have with other men. She doesn't have a job and has been in school. Her husband pays all the bills and loves her so much even though she has shown nothing but hate and malice towards him. She has brought other men into the house and labeled them as friends but they are more than friends. One guy used her for her house though they never had her body language (at first) Showed she liked him. She now has a guy in there that she just met less than a month ago and has held hands with him and hugged him, while her husband is there. I dont' think she should be using his money to galavant with these men and I especially don't think that she should be bringing them home and letting them stay the night. She laughs at her husband flippantly and she ignores the kids feelings. She says she cares about them but refuses to put them in counseling. She refuses to go to counseling herself. She was molested as a child and she never talked to anyone about it and the person who did was never brought to justice. Her mother has had a history of mental illness and my best friend says that mental illness is a crock and that people can help it (at least her mom can anyways) But I know that science has proved its not true. She doesn't listen to reason and she still wants to bring these men into the house and let the kids see her with them (not ually.) This is wrong on so many levels. She has also started smoking pot with this guy. They don't smoke it in front of the kids but they come back to the house stoned. To me that is irresponsible and stupid. I told her before she should talk to a counselor and she said no and that they don't do anything. I am at a loss...Those kids mean everything to me and I want them to be happy and healthy. Her oldest hates her and her second oldest is repressing everything her daughters don't totally understand but they know something is wrong. I don't know what to do. I am tempted to call child services. I NEVER brought guys into my daughters life after my divorce and my bf now didn't meet her until we had been dating for 9 months. I know what she is doing is wrong and I know that she has been happy then sad all of a sudden and she is trying to find that feeling of "love" which doesn't exist. Love is a choice and lust is a feeling. What should I do? What should I say? Am I wrong to worry about her bringing strange guys that no one knows except for her?