Chloe, assuming the two know each other, is the most ideal candidate to be someone Chase acts as an older brother for, lacking any younger siblings himself. She's younger, from somewhere far away (even if that was a few years ago) and in general is a person he could be friends with (if you're interested in being quite friendly?).
Oleg's dislikes are relatively in line with Chase's, and his like of honest suggests he's someone Chase could certainly get on with. Both seem like they're right countryside boys.
As mentioned by Meikle its possible Chase & Lillian know the same people, but as she also mentioned the have rather different interests in friends. His dislike of large social groups would suggest he's probably not overtly familiar with her.