James had managed to calm him away from tearing Regulus' head off, but he wasn't yet convinced on his brother's intentions. He wasn't in the least doubtful of Bellatrix's. Sirius couldn't sit by and let fate collide his cousins, but he couldn't rely on Dora not to fly off the handle - he had, after all, and Dora didn't seem to be much more evenly tempered.
Andromeda had always been his confidante on family matters. She understood, and she understood them. Something in Sirius felt eased knowing that Andromeda didn't find it strange to understand the motivations and intentions of the family you'd left.
Dear Andi,
Hope you and Teddy are well. I need to speak to you about something pretty urgently.
How about if you bring Teddy to the park on Wednesday?