how to buy heirs in family property

Heir property? my grandfather built a home on his own land and now he is deceased and his wife are deceased. The property fell in care of the oldest son and others. There were seven children born to them. all are deceased except 3 the oldest who the property is in care of is on his death bed at the age of 80. Two sisters including my mother and aunt sold their share to the oldest brother who is on his death bed. Which now leaves me out of my grandfather property. i have asked other siblings in california if i could buy them out they said yes because i want to keep the property in the family.There mother is deceased and all six of her kids are still living.One adult is in jail and won't be out until 4 years. the property is located in louisiana. i will have to fly to los angeles and get them to sign papers. My questions are what documents do i have them sign? What should the document state? How do I handle the paperwork for the cousin that is in jail how do i get him to sign? What papers do i file with the ruston, la. court house. will i need witnesses? I plan to do it all at the airport and exit? Will i need a notary to meet at the airport in los angeles? After i get them to sign, what papers do i file? What if all six cousins don't sign and only two or three sign? please answer bysept.6, 2010 of short after. could you please send me step by step procedures of what do and examples of the forms i need? thank you with gracious gratiude!