Iam With Someone Who Is Diagnosed With Bipolar, He Was

Iam with someone who is diagnosed with bipolar, he was so sweet then, very caring. He moved in with me, he said he’s okay and stopped taking his drugs. He said neing with me is jusr whar he needs and that i am better than any drugs he took coz hefeels great. But after a few weeks hehas changed as if he’s a totallydifferent person. He treats not like before. He’s irritable! Talks fast and went back to smokimg. He treats me indifferently started sleeping on the couch but still have sex once in a while. Hethen told me that we’re just friends. Is this an episode od bipolar? Is he still be going back to when he was before like when he was sweet and caring person? What can i do to help him?