My Mother Is Dying And A Random Person Is Threatening Me With Libel, Convinced Mom To Be Her Poa (and Making Decisions If Mom Should Have Her Legs Amputated)

TL;DR Mom has cancer and is in her deathbed, dad shot himself last month as he couldn't cope. Some random person came out of the woodwork and has turned mom against her children and has generally been an awful person. No respect, care or concern for the family. I found out that they had won a Medical Malpractice lawsuit in 2014 for a million dollars and her ex husband, which is also in the situation, had a whole lot of debt and debt related lawsuits in the past, which seems very suspicious (thanks Doxpop)

She has somehow convinced mom to be her POA (or medical directive, but we are unclear) when mom been so out of it she doesn't know who people are or how to answer her phone. For whatever reason, the hospital has deemed mom to be "of sound mind" 10 times now, and every time mom comes home, she lasts three to four days before going back to the ICU. It doesn't help that mom, in her deteriorated state, has been very loud about her money and business.

Of course, I'm not too happy with this and posted this on my Facebook (as for the Libel portion)
"There is one [REDACTED] that has been commanded to cease and desist contact with my mother and to stay away from the hospital. She's been fighting with family members and cursing at my aunt, along with her associate Brian.

The family is unsure as to her intentions, but [REDACTED] is attempting to receive POA over my dying mother and is highly suspect while she is on her deathbed.

There will be hell to pay legally if you choose to keep meddling in this, [REDACTED]."

I'm not proud of it by any means and since removed it. What I do have is a signed affidavit from my aunt recounting the poor experience with this person at the hospital and an opinion of their character, and an affidavit from another sister about this person's abuse towards her, and well, my other sister too.

I made the post after hearing from mother's estate attorney that this person shouldn't have ground to stand on and shouldn't be meddling in affairs as not designated in the will, but have since learned that this is incorrect (as mom changed her medical directive/POA by verbal agreement). While I was emotional and at the time posted what I believed to be true (same day the hospital called and said my mom will be dead in a dew days), I'm still concerned as it's the last thing I and my sisters should be worried about.

And well, the hospital said this morning that they can remove mom's legs which may kill her, or not and it may kill her due to extreme blood clot, and the thing that sucks the most is that this random, terrible person has full authority to make medical decisions and us kids can't even call the hospital for updates or visit mom. She's trying to get mom to come home with her instead of to hospice and didn't want us to know.

To recap:

• I've deleted the post and no longer talk about it on social media
• Made my blog private
• I informed this person that I believe my opinions to be true and I'm open to being corrected (the day she blew up my phone and threatened me), and deleted the post in good faith
• We've ceased communication with this person completely
• She called and harassed my little sister this evening and made nasty comments about the lawsuit, how mom is going to evict her if she ever comes home, and if she dies, never speak to us again (thank f*cking god)

Of course, I hired a lawyer for emergency guardianship and I've since ceased all communication with this person and removed all posts, but do I really need to worry about this legal threat from this awful person when my mother is dying and may soon not have legs without any input from her family?