My Mother took my SSI money for herself

Ok, I have Cystic Fibrosis. When I was 12 yrs old, my Mother received $42,000 in SSI money for me, for backpay. She was not living with me and I was being raised by my Grandparents. My Mother took the money, bought herself a house. Then moved my 2 younger sisters into the house along with her current boyfriend (their father). She never even asked me or my older sister to live with her. I lived with my Grandparents from a year old up to 27 yrs old. Is there a way I can go after my Mother for this money? She's been terrible my whole entire life, so I really don't feel bad about suing her if I can. Thanks!