I happen to be bipolar and schizoeffective. There are different levels of bipolar disorder. For the people saying he "sounds like a serial killer" and "he's a keeper", you guys obviously never knew anyone with a mood disorder. We're not easy to get along with. But we do have people fall in love with us. My mood disorder kept me from marrying my husband for 15 years. Now we've been married for 3 years. (Total of 18 years together.) I am sometimes manic and then I crash and am depressed. I am sometimes very paranoid and believe people are staring at me and/or talking about me. Sometimes we make rash decisions. So OP's husband could have had a manic phase when he blocked her sister and forgot about it. You have to understand the disorder before passing judgement

Sorry I meant OP's sister's husband

I'm glad you're there for your sister.

I'm sorry, but how in the world would the cops be able to do anything at all? Oh no, my sisters husband blocked my phone number on my sisters phone, better call the police! That's not even a crime...love how people think officers have a magic wand they can wave and fix all their problems

Oh wow, that must make it even harder on her.. I hope she can get out soon. My fathers depression made him short tempered. He kept from hurting my mother under her threat of if he hit her she'd leave, but it didn't stop mental or emotional abuse. When she was going through the divorce, he did hit her but police was called and it at least strengthened her case. She found out later, though, that while he kept from physically hurting her he didn't for my brother. On his meds he is a lot better, but it took her leaving him and him dealing with it and eventually finding someone new to get him to that point. Don't expect them to change if you stay with them, I truly think if my mom stayed he wouldn't have become who he was today. Sometimes leaving is best for all parties. Since he actually chose to change, my brother and I have a relationship with him. But my brother cant forget what happened when he was little. The divorce was finalized when I was 4 but I still have memories of hiding in the dark crying because of the fighting and somewhat of being in his arms when he was hitting my mom. This is really long, sorry, I just wanted to share. Even if he doesn't hurt her, he could hurt the kids. If not physically, then mentally.

Report any suspicious anything to law enforcement anonymously.

Without proper treatment, Bipolar is a serious problem. I have it, but more relevant is that my now-ex-stepdad had it and it was one of the factors that lead to his mental and emotional abuse of me. He nearly drove me to suicide. Talk to your sister about trying to get him better treatment before things get worse.

Exactly. As a person with BPD, I am sick of people throwing that word around to describe all sorts of incredible negative CHOSEN behaviors. He is an asshole. That's not a mental illness. Spreading that sort of misinformation means that those of us who already deal with mental illness also have to deal with social ignorance and stigma. The truth is, 99% of the time, you can't pick us out of the crowd. I take my pill and I come across as perfectly cognitively normal. I hang out with my friends, I have fun, I cuddle kittens, I work on my Ph.D, etc.

He sounds abusive.

Is he diagnosed as being bi-polar by a doctor? If not, then you can't really say that he is, no offense. Good for you though, OP, for trying to be supportive of her!