Finding out my legal rights?

We have a family home that is available,I am the only girl with seven brothers,one is deceased,one is incarcerated,and another one is mentally handicap who is living in the home,another brother lives in another state,but I don't know his whereabouts. There was never a living will,and a secession has not been open up.I need to move in the home,to take care of my mentally handicap brother where I will be the payee. The incarcerated brother has left a girlfriend in the home,she has been their for about a year and a half,she has two children of her own which is not my brother children. She will not leave the family home.What is my legal rights in the state of Louisiana to have her remove from the house,the house is paid for nor does she have to pay utilities because of my handicap brother. She does not take care of him.I need to move in so I can take of my brother,What is my legal rights in the state of Louisiana to get her to move out and for me to move in, She refuses to move,Do I have to move in while she is still there? What is the best and legal way to go about this situation?