emergency custody and CPS

I have a family member who is trying to obtain emergency custody of his two year old daughter due to her mother being put into rehab yesterday. Her family is imminent about keeping the baby away from him, but he was able to bring her home with him yesterday and is trying to get an ECO so they can't keep him away and because if she's not with her mother she should be with her dad in my opinion. Anyway, cps is coming to his home to visit today. Is this a normal routine or is something bigger going to take place?