I don't' think Meena cares whether Ethan finds his mother or not. Like most things she does she seems more motivated by manipulating and controlling Manpreet. Like you say she could have given the phone number directly to Ethan without involving Manpreet, but I wonder if she is hoping that Manpreet will get caught out, and get into trouble, or even struck off. She seems intent on getting some sort of revenge on Manpreet for things that happened in the past. Like you I doubt she could have obtained the phone number so easily. I am not sure with an attitude like her's, she is entirely suited to being a nurse.