This is bipolar disorder right?

Ummm I hate to say this but there's actually not much you can do, but to be there for him / her.
He/she needs professional help, drug treatments are the most effective, I've read.

What you need to understand is that these people are actually mentally unfit for relationships, so many things they do / say may come off really.. wow, if you catch my drift.
And, uhm, try to talk about it with close friends or online friends, don't go through this on your own.

Hope this helps.

__________________