The Midnight Train to Georgia singer claims relations between herself and Shanga Hankerson hit a low when he attempted to extort her if she didn't give him more time to respond to her lawsuit over the Georgia chicken & waffles chain that bears her name.

According to new documents obtained by TMZ, Gladys has accused her son and his legal team of threatening to go public with claims she has been diagnosed with Alzheimer's if she didn't comply with their requests.

Shanga and his lawyer even filed papers suggesting the singer had a "lack of mental capacity".

Gladys denies she has been diagnosed with memory destroying Alzheimer's, and she's accusing her son of trying to "embarrass and harass" her.

Knight has won a default judgment demanding her son removes her face and name from signs and promotions for the chicken and waffle joints.

Gladys admits she gave her son the OK to use her name and image for the restaurants back in 1999, but she asked him to leave her out of promotions earlier this year (16), when the diners were raided by the Georgia Department of Revenue and her son was arrested.