Ah, didn't notice this thread.
How your friend used Blood Brothers is how I've always used it. It's very helpful as a way to generate favor for the faction, and it's a pretty interesting shenanigans play altogether. The only thing is that you can't disengage from it, since that is triggered by damage from an enemy.
As for the healing, yea. Same goes for any other model being healed and their effects being triggered, whether it's Anum's
, a model being healed by Gaius and unmarking the favor box, you name it.
Also, since
is basically the crowd cheering or going wild, I'd like to think that from a flavor standpoint, the crowd sees spectacle in this brotherhood demonstrating their bond and pushing onward.