My husband and I own a house in Florida that we bought for my Mother and Father about 15 years ago. My Father passed away almost 2 years ago. My sister and her husband moved in with an agreement that they pay rent and their share of utilities. Her husband is on disability from the military. She worked for a while then lost her job. To make a long story short, they haven't paid anything for over six months and are draining my Mother's savings. How do I get them out of my house?

You have a choice. You can give them a written 3 day pay or quit notice. If they don't pay all arrears in 3 days and they don't move out, then you file for eviction. Or you can give them a written 15 day termination of lease notice. This gives them 15 days to move out after which you start the eviction process.