Fixing and Flipping my mothers home!

Hello all! 

I have a question for you. My mother just downsized from her home to a condo. She wants to sell the house to me at a great deal (her home is paid in full). She is encouraging me to fix and flip it and use the money to fund an addition on my primary that she knows ive been planning. 

She has lived at the house for about 7 years as her primary and I know she wont have to pay capital gains.

So my question is, if I get added to the deed and I fix and flip the home, pay her what she wanted and kept the profits would she still be able to use the capital gains exemption.

We already have an appointment to get me added to the deed, is this a strategic play or am I missing something? Thanks in advance!