So sorry to hear of your suspicions about your Mom. My husband suffered from dementia...I guess we all call it Alzheimer's because it sounds better and people understand what you're referring to. Alzheimer's is only one of several types of dementia. Symptoms are all very similar.
With regard to your Mom's short-term memory: I found it worked best not to argue with or correct my husband...or try to adjust him to reality. Just agree with what your Mom says whenever you can. (She'll forget in 3 minutes anyway.)
You have to learn to lie judiciously. It reduces her anxiety and your frustration
Please, please, if she asks about a deceased love one (like her mom or dad,) don't correct her. She'll experience hearing about a death as if it were the first time and probably cry.
If she wants "to go home," just put her in the car and drive her around the block. By the time you get home, she'll recognize the place. Or not. But it's worth a try.
Get a copy of "The 36-Hour Day" at your library or bookstore.