i think tolys and nikola are both delusional in different ways ("I am a temporarily embarrassed superpower"/"God loves/hates Me, Uniquely") but there's just enough overlap ("people are laughing at me and awaiting my downfall") that they would enable each others delusions if they were ever in the right place at the right time.
gilbert i think is less susceptible to delusions tho i do think he suffers from them occasionally especially during / right after cold war era. but he Is just the right combo of kind of paranoid & high strung + in a kinda shite mental place once he effectively Doesn't Exist anymore that i think if u get him drunk enough and catch him at a bad time u can make him a victim of folie imposée
dimitrie is Not Delusional but he will just roll with it out of both morbid curiousity and also concern for what they would all do to each other if he intervened. i think he accidentally enables them initially and then enables them On Purpose sometimes. again out of morbid curiousity. studying the folie à trois until it gets out of hand