My question involves landlord-tenant law in the State of: Florida

Hi all. I am currently the adult daughter (19) currently dealing on the outskirts of an eviction between my mother and grandmother.

My grandmother (79 years old) has been living in my mother's house for almost 10 years taking care of me when I was a minor, paying her a monthly rent fee of $1000/month and covering all utilities while my mom lived in a different house. As far as I've been told, there was never a "lease agreement" signed between them, and it was all off of "you'll pay me this much per month" but there was never any legal lease signed by either party. Currently, I am a college student living on my own 6 hours away so I've been an outsider in all of this looking in on both the actions of my mother and grandmother. When I moved to college 2.5 years ago, my grandmother got a job to both keep her attention (because she didn't have to look after me) and to help pay her bills outside of Social Security and money market accounts that pays out monthly so she can cover her expenses. She has never been late/late without reason to pay my mother the $1000/month. Recently, my mother moved back into the house with my grandmother and apparently they always fight. Verbal altercations with both parties ending up in tears happen regularly. My mother has allowed (grudgingly) my grandmother to continue to occupy the house under the condition that she's still paying rent. This past month, my mother told me my grandma refused to pay her rent, so I investigated into the situation. According to my grandmother, she had "bills to pay" and couldn't dish out $1000 this month. I'm unsure what these expenses were but that's immaterial. Anyway, in any other situation with any other landlord, if you don't pay your rent, obviously legal action will be taken against the tenant. Cool. So my mother tells my grandmother that she has 30 days to move out. As she's pretty elderly, and we've been doubting her compentency for years, she's been looking for new places to move, but my mother keeps bombarding my grandmother with nasty letters and has moved her stuff outside/into her room/out of the kitchen/etc. I do understand my mother's frustration with living back at home with her mom (as a dating individual) and that my grandmother is very much responsible to pay her rent monthly and on time, but I feel like she's being EXTREMELY unprofessional with the way she has carried out the 30-day notice. Almost every day, my mother leaves a note on my grandmothers bed spewing expletives, that she's "miserable" living with my grandmother, etc. It's all become very out of hand.

Today, I called my mother to let her know when I'll be returning home from college for spring break. She has informed me that she has taken a motion for eviction against my grandmother and that she'll be being served in the next few days, so to be ready for all hell to break loose.

I guess my main questions are, what can my mom ACTUALLY do (and not just threaten to do) to my grandmother without a written, signed lease? Can she just throw my grandmother's stuff out by the side of the road (like she's done many times before)? Should my grandmother get an attorney? If my grandmother is deemed legally incompetent, can my mother force her to move out? Is there anything my grandmother can do as recourse for my mother's behavior towards her?

Thank you!