My sister got my mother to sign over everything to her 10 years ago and basically cut me out of everything.?

I was not consulted and it as all done behind my back. My mother was 81 and senile. She got it all signed over without my knowledge and even if she had died in the meantime, it would have gone to my kids not me. I cannot believe a solicitor would not have asked whether there were any other beneficiaries? It is my belief, although difficult to prove, that she either misled the solicitor e.g. "inferred" the kids were hers or "inferred" I was dead. Is there anything I can do about this as my mum died 12 months ago and I only knew she had money because one of my kids let slip that their auntie had given them some of grans money left to them but she told my kids not to mention it to me. I have since got copies of the will from the probate office and discovered what she has done, she "conned" my mother into moving in with her after my father died, signed over all her money, then within 2 years transferred her to a nursing home, presumably paid for by the state and not my mothers estate. This is where my sister inferred to me that mum would never leave anything as it would all go to the nursing home for her welfare and upkeep. Codswallop. It's paid for all her house improvements, new cars and holidays. I have been well and truly had. Now I want to get even.