Hisoka only joined phantom troupe so he could fight one Chrollo the most powerful nen users.
Hisoka was badly wounded during the last battle, and someone must've used Night Sight to heal him, giving him a bit of enhanced nen.
Lily, Artemis, Demon, and Demigod showed up to visit Hisoka, in his first real nen experience, even though a member of the changeling team should've showed up to greet him.
Lily and Artemis argued with Him, as she had the genius idea that since his entire body was hurt, he could use Night Sight as a medicine for other team members.
Hisoka simply thought that it was a terrible idea, and neither of them were helping to mend their broken relationship, though they both seemed to be listening to him, as they showed no hostility or anger.
It took some persuasion from Demigod to get Hisoka to stay and eat something but he still could sense the Hisoka in the Phantom Troupe.