Well, since they are all visible, he may get involved again - either by coming upon them or them calling him. I'm pretty sure he will get involved - the whole brother-vampire story is too good to leave hanging.
Aside from that, I fully expected him to bring back either Kei or Sai. He said he'd get them all back - them ought to have included Kishimoto at least. Although in the case of Sai it'd be kinda cruel - yeah, nice to see you too, you're even more over me than last time buuuut - now I have a girlfriend so scram. Still, she did save his life.