We don't know what happened with their relationship with Gillian, everyone has been vague about Gillian until her reappearance. We know that Gillian left the city for awhile, and most of Ian's friends have been very sympathetic to his state of mind whenever Gillian gets brought up. So it seems safe to assume that, even if they didn't outright end their friendship with Gillian, that contact was lost between them regardless.I agree but...
ffive did Ian's friend's ended their friendship with Gillian(Chameleon) when she cheated on Ian?
If not than they might not end their friendship with Lena.
I get this impression that when Gillian(Chameleon) cheated on Ian, none of Ian's friend ended their friendship with Gillian! Ian's friend may not end their friendship with Lena too. I might be wrong!
Jeremy was the only one to know ahead of Ian that she was back, and he kept quite about it out of concern for how Ian would react; considering how he ended up reacting, it seems Jeremy made the right call.