Ashley spoke with Diane Sawyer on 'GMA' about Naomi's death, the day before she was inducted into the Country Music Hall of Fame.

She explained ... "Her brain hurt, it physically hurt and I'm tasked with an exceedingly difficult task in disclosing the matter in the way my mother chose to continue to live … because we don’t want it to be part of the gossip economy I will share with you that she used a weapon mother used a firearm so that's the piece of information that we are very uncomfortable sharing but understand."

Ashley said she was the one who discovered Naomi's body ... "It was a mixed day. I visit with my mom and pop every day when I’m home in Tennessee, so I was at the house visiting as I am every day. Mom said to me, 'Will you stay with me?' and I said, 'Of course, I will.' … I went upstairs to let her know that her good friend was there and I discovered her. I have both grief and trauma from discovering her."

Ashley said there was a disconnect, or better put a wall, between the feelings the outside world had for Naomi and the way she felt about herself. The mental illness wouldn't allow Naomi to process the love and worth others showed toward her ... she only felt self-doubt.

As she put it, "Our mother couldn't hang on until she was inducted into the Hall of Fame by her peers. That was the level of catastrophe of what was going on inside her."

As you know, Ashley and her sister Wynonna were at the HOF ceremony and tearfully paid tribute to their mom.

On 'GMA' Ashley explained she wanted to put a spotlight on mental illness ... "My mother knew that she was seen and she was heard in her anguish, and she was walked home. When we're talking about mental illness, it's very important to be clear and to make the distinction between our loved one and the disease. It's very real, and it lies, it's savage."