Legal Question in Real Estate Law in South Carolina

In short - Probably not. Your grandmother as you said has a Life Estate. Therefore, she is allowed to do as she wishes with the property while she is alive - so long as whatever she does with the property does not endanger it, devalue it, or make it worth any less for the person(s) getting the property at the time of her death. If she chooses to let your mother live on the property during her lifetime, and your mother is not hurting the property whatsoever and understands that when your grandmother dies, she will have no rights to the property, then she is probably safe.

However, please note: It is always best to have an attorney actually review any and all documents regarding the parties and property involved before anyone can say 100%. There can always be stipulations and ways around things that could be put in the documents before they were executed. So please, take this for what it is, advice and opinion on just the information provided. Without additional information one cannot say for certain either way.