I've just read through most of the threads on this here on FR, but I have to work - and sleep - sometime. This is the first I've heard re: the sister's boyfriend being black.
The last info I had was that the sister was dead, but the boyfriend was still alive and hospitalized. Got a link to the most recent updates?
“Suspected White Supremacist Shooter In Dayton Was Reportedly Angry His Sister Was Dating A Black Man”
https://newsone.com/3883585/dayton-shooter-killed-sister/