How should I go about this plot in my fic?

Basically, in my fic the original Isaac gets resurrected, and he becomes really close with three people from other worlds, Duo, Eita, and Yoshito (with one of those people from another world and the latter 3 being part of a magical boy group Isaac leads.)

Anyways, when they all get to Tokyo to help liberate it from the GMs, everything goes south fast. Curren and Bertro find out about him, and they think he’s an imposter (considering the “real” Isaac is with them.)

So, they decide to take everything from him, kidnapping his loved ones and bullying him, which inevitably causes him to snap.

The problem is, I don’t know what they’d do with everyone. I was thinking of having them brainwash his loved ones, or experimenting (read: making clones and experimenting on those while passing them off as the real ones) on most of them (save for Duo and Yoshito,) but I can’t really think of anything beyond that…