What a great thing to happen to that kitten.KoKo will take a little while to adjust.But he WILL ajust.Some take longer than others.You may see them playing a bit together later.
They'll be company for each other too even if they don't hang with each other.They just look at each other and that's comfort to have another cat around for Koko.I don't mean now..later it should happen.Be patient.I have 9 cats now and it's alway an adjustment.Good luck and I'm so glad you kept him.Carla