I really think that the best thing for your girlfriend to do is to speak with an attorney in your area on the matter.  The courts try and make sure that the children have a good relationship with both parents and aside from her being able to obtain support, she can surely enforce a  visitation agreement issued in the matter. And she should indeed do so each and every time he denies her access to the children.  Now, as for the reasons that she was dismissed from work.  She violated company confidentiality and she acted  unprofessionally in the workplace.  As for whether or not this is tantamount to a blip on her moral charchter that could effect her ability to obtain custody, the courts look at matters "in the best interest of the child."  If he could use this against her in the way stated above then it may have a bearing on the outcome.  But really an attorney in the area would know best.  The local case law will be the judge. Good luck.