Neglegance at a rehab..

My ex-wife was recently sent to a rehab called the lighthouse. While there I was asked by her if our 4 kids 3 sons ages 3-4-9 and my daughter age 8. While there I found out she had a new boyfriend that had checked himself into the mens dorm of this rehab. Come to find out they let my all my 4 kids including my 8 year old daughter stay the night in the all mens dorm with around 40 -50 other drug addictided and ex drug addicts MEN on 2 or 3 diff. occasions. Now when they got back to my house last night and told me this I was furious and got in contact with their mother told her what I was gonna do about this. Well today I got in contact with the head guy at the lighthouse and insisted that they THOUGHT that the 4 kids were his real kids even though they have my last name and admitted that his staff is susposed to check into these things and apologized over and over. I told them did they even ask my kids if that was their dad and he said no there was absolutly no check into it. He stated the rules are to have any kids stay with a patient they have to be the actual parent and that he would get onto his staff about. Not to mention they have bed bugs all my kids have bites all over them from it. It is full neglegance on the rehabs end to check into to see if these kids were his and to have all my sons and especially my 8 year old daughter staying with a man they barely knew in a dorm of 40 to 50 other MEN. I just don't know what kind of an attorney to contact or if there is a case that even can be filed but I would appreciate any info I can get . Thanks in advance and sorry for spelling errors.