Personally I wouldn't. She could be just talking the bloke up- he might not give her anything, in which case she'll be in sh1t street with the kids, alternatively if he is just lodging he might indeed give her something and she might have declared this to the council so have nothing to hide. She's entitled to child benefit no matter how much money she has, it's only council tax benefit and LHA which would be a potential issue and then not necessarily. What is her main income, because she doesn't appear to have once since ctb she won't even see, LHA will only cover her rent and child benefit is about £20 per week?