Warning sign for schizophrenia?

My brother was diagnosed with bi polar. But I think this may be a mis-diagnosis.

He experiences frequent delusions (thinks he’s not apart of our family, thinks my uncle is his father, believes some one is trying to poison him, thinks we’re all conspiring against him, etc).

He’ll become very obsessive and fixated on the past, especially when he’s having an episode.

He spends a lot of time by himself. Is super fearful (at times, too scared to walk into the store or get a hair cut).

He’s also spoke about a genie- who he can’t talk about. I know that he’s had encounters with this “genie” but he refuses to speak on them.

For those of you who are schizophrenic.... what were your early warning signs (as I don’t believe this is bi polar)? And how can I help my brother?