How do i legally fundraise for my mum?

how do i legalize a charity for fundraising to help my mum has she got a brain tumour and they cant operate or anything but they upped her steriods to 24 ml 2 weeks ago she had a stroke caused by the tumour she can just about speak properly she has lost the right side feeling cause the tumour caused it but i cant sit back i found in boston they got top doctors who will operate can you help and tell me how to become legalized to begin fundraising thanks caroline xxx as she is 45 im 29 and another 2 sons and a wondeful husband