Having been around the block once or twice, there are several items to note concerning the subject of signatures or autographs (two different things, BTW). If the signature or autograph on a warranty deed is NOTARIZED, it is more difficult to call the deed into question. If the signature/autograph is NOT NOTARIZED, you may get some headway especially if you can prove your mother acted under duress or was coerced. Also, only your mother can declare any so-called "signature" to be her own handwriting.......OR NOT. No one else has this power. The subject of senior or elder abuse also comes to mind. Most people over 80 years of age don't possess near the cognitive and rational skills they did when they were younger. This is why senior fraud is so rampant, the fraudsters know it is easy to work over a single eighty plus year old man or woman.
Unless you want to lay down and give up the goodies, a quiet title action may present a remedy for your situation. Most people and many lawyers know very little about quiet title actions. This is why you need a SUBJECT MATTER EXPERT to handle the matter.
Here is a good read to get you acquainted:
https://www.forrylaw.com/the-real-property-scalpel-a-quiet-title-action/
and here is a SUBJECT MATTER EXPERT located in Marietta, Georgia. Yes, he charges a few bucks to do the legal work but if the land is worth a lot, $2500 to $3500 to initiate a quiet title action is more than reasonable.
Normally, most lawyers charge nothing for an initial consultation. It is my opinion that it is best to set up a FACE to FACE consultation and bring all the paperwork you can to the meeting. 80% of all communication is NON-VERBAL which means a mere telephone consultation may not get you where you want to go. Also, be prepared to stroke a check should you like what you hear. Please take a few minutes to go through the various links on his website, at a minimum you will LEARN a few things that may help you.
Georgia Quiet Title Lawyer – Quiet Title for Tax Deeds, to Remove Liens, and Clear Title