You want to stay away from attorneys. Once they know your living in the UK their eyes start to roll with £ signs like a fruit machine. If your husband has no contact with them and has not had contact with them for so long the you obviously have sole responsibility for them and the visa application form only asks if you have sole responsibility for them.
The main problem you will have is that of proving that there is no one else who can care for them in Phils because they have been living there without you for so long, but if you can get an official letter from a doctor stating that your mother is no longer capable of looking after them due to her illness, I think this might help somewhat.
Iain.
