Some say Dylan followed Eric's lead, whatever Eric did Dylan did as well. I think Dylan just did whatever any friend did that he hang around with. But more with Eric because he was the closest to him in emotions and stuff. I think Dylan stuck around Eric because Eric had ideas on what to do a lot of the time that would make Dylan interested. I'm not saying that Dylan followed Eric around every passing moment, went with everything he did. I just think with Dylan's shyness and how he didn't seem to say much (always usually saying "yep" "yeah" or a simple nod when talking to someone) made him seem like that.
Dylan with Eric
There are others saying Eric followed whatever Dylan did as well. Some say that Eric usually sat by Dylan