When I first realized that my DS was of a "different stripe" I was relentless in my pursuit of answers and information. I lived on Hoagies, on here, on the Davidson site. I get it, I understand her need for answers.
Hi Shari, good to see you around here again! Maybe the mom will ease up if you explain what you wrote, letting her know that you can relate to her need for knowledge, but then let her know that now that you are at a different stage of this journey, your interest has moved on. Apologize that you don't have the same zeal for these discussions, but that if she goes to [recommended GT psychologist] for testing, then she'll likely get many more resources and hopefully some more contacts of families in similar positions. (I know that the psychologist who tested my son had a list of parents willing to talk BTDT with newly ID's gifties.)
If that doesn't work, or if the advice of others here doesn't work, sometimes you just have to be very blunt and end the relationship, especially if it is causing undue stress.
good luck!