Naturally Cobes, even with his questionable sense of social understanding, has been able to see the problematic cycle Jessica is unable to remove herself from. Its taken practically no time at all for Cobes to run out of empathy. Yes most of his decision-making is probably born out of her trying to tell him what to do, but even he sees there isnt going to be a payoff with investing in a relationship with her.
This will hopefully be the right decision for Cobes. They haven't even met, and he already had enough of her manipulative behaviour. Constantly propping up someone who is eternally reduced to "woe is me, im literally unloveable, no one has EVER loved me!" isnt worth it. Even for the BOY in the dryest of spells. Ideally he can stay away, block and cut her off before she predictably escalates the self-harm and threats of suicide into blackmail and the distortion campaign when she inevitably 'splits' on Josh. Buuuuuut my hopes are probably a little high for all this regardedness.