IANAL - While your mom's total estate is well under $5M*, you would need to file a gift tax form with her annual income tax return if you have her give you or anyone else more than $14,000 in a single year. No actual taxes would be owed, but she (you) would be legally required to do that additional paperwork for her income taxes.
If you stay under $14,000 per person per year, you have no extra paperwork burden.
Also, do you have any plans for your mom to use Medicaid to pay for her end of life expenses? If so, be very careful with the gifting. The federal government is very against anything that looks like hiding her money to transfer medical expenses from her estate to the government.
*The big caveat for the $5M (technically $5,340,000 for 2014) estate tax basic exclusion amount is that STATES can apply death taxes to a smaller amount and some states tax both the estate and the inheritance. If you or your mom live in Pennsylvania for instance, you may not be as safe from estate and inheritance taxes as others.
Thank you for sharing what your mom's estate attorney had to say.