The first thing Michael did, even before Molly finished speaking, he reached for hands. He gripped Charity's hand, and he gripped Molly's hand, forming a bridge between them. Molly and Charity had a strained relationship, largely due to Molly's foray into wizardry.
He hated seeing them at odds, even just a little bit. With Molly's announcement he felt the void between them enlarge to a chasm that would take a lot of time and patience to breech.
He drew a breath. "You seem to be handling it well," he said after a moment. What could he say, really? He couldn't tell her what a bad idea it was, he knew how these things worked, she likely didn't have a choice. Harry Dresden better hope it was something he couldn't have prevented, either.
But that was neither here nor there. What mattered right then was reassuring Molly, and offering her the love and support of not just her parents, but her entire family.