I need to obtain guardianship or have a judge appoint someone. My sister is trying to get it but has, no employment or stable living situation.

I need to obtain guardianship of my Mother who has dementia. My sister is saying she wants to take over my mothers finances and everything. She has filed for disability for herself, has no income and stable living situation. Someone else has their name on her lease because she has been unemployed for at lease 10 years. She has not come around in years to help my brother and I, and now I fear she sees an opportunity to get money. I have always had a stable, well paying job and wanted to know how the court views this. There is so much more, but wanted some initial feedback. I need to file as soon as possible.