Is there any law that can help me and my kids?

My ex suffers from a mental illness, I want to move out of town but we have three children together.  I am afraid that if he does not get the help he needs he could do something to me or my kids.  I want him to get help so my children are safe when with him.  Is there any way I can get help about this? I know I can not force him if he does not want to but I just think that otherwise he will choose not to go see a doctor.  Please help.  He suffers from bipolar disorder and right now he is having a bad episode, but before this he did not want to go see a doctor when he was fine I begged him to go and he said that he was ok, that he was going to be able to control it. In other occasions I have been always there for him and help him and support him, even when he was so verbally abusive and emotionally but I dont want my children to suffer this.  Please Help!!!!!