He becomes addicted to attending support groups and pretending to be a victim, but the presence of another impostor, Marla Singer, disturbs him, so he negotiates with her to avoid their meeting at the same groups.
He becomes addicted to attending support groups and pretending to be a victim, using different names for each group, hence why we don't know his real name. Until, the presence of another impostor, Marla Singer, disturbs him, so he negotiates with her to avoid their meeting at the same groups.