Thank you so much, ladies for your thoughtful and supportive replies.
I DO get that I need to let go of why this woman is invested in my son. I just posted a new thread because things have now changed, with a phone call to my ex yesterday-difficult child is wending his way back to me. This mom has supposedly lent him the train fare to get back here. I don't believe this-I think he got it some other way...
But she texted me yesterday and said she wants to talk. Ugh. So the dance continues.