Hello. I am new to writing in forums about my personal life but I feel like I need advice from an outside source.
I have been having problems with my brother-in-law for the past few months. We have known each other for about 13 years now and have gotten along fine until recently. A while back he started investigating mine and my sisters past. He came to me for information saying that it was to help her deal with issues that she is having as an adult. At first I freely gave him advice, but it was not too long before his questions became demands. He started saying he had "proof" this or that happened and that I should remember things this or that way. When asked for my opinion he'd argue with me incessantly if our opinions differed at all. When he asked for advice and I didn't have an answer (I would say "I don't know") he would nag me until I made some sort of suggestion, then tear the suggestion down. Eventually I simply stopped talking to him. This still didn't stop him, he'd message me on instant messenger saying he "had permission from" my sister to ask questions. I did my best to stay civil by telling him I just didn't know.
A few days ago we were playing an online cooperative game. We argued about losing, which in my opinion is just part of the game, and left to calm down. He messaged me on an instant messenger claiming that I had made him feel like I was putting him down (fine, I can apologize for that), but then he went on to say that I was acting like the abusers I had in the past, naming them specifically and actions that they had done (which none were done in the argument). He even went as far as to say that I was ignoring him like I had ignored the people who said that they were being abused by my father when I was 8 (that is a whole different story but relevant to this point).
At this point I completely lost it. I had gotten online to make amends, it was a stupid argument anyways, and I find myself faced with being compared to child abusers, molesters, and being shamed for decisions I made as an 8 year old. I told him to never talk to me again, that I would not stand to be compared to such things over such a small argument, and called him a piece of s**t.
Yes, I realize the last part was petty but I was, and still am pretty furious about it. I don't feel like a small argument justifies anyone to be compared to disgusting people nor does it justify shaming someone, and I don't feel bad about my response. I do, however, realize that this will affect my relationship with my sister. She and I have always been incredibly close, probably because of what we went through together. Because of the way he has treated me, I feel afraid he is doing the same to her, standing as a pillar of things past instead of a support to build a future. I also fear how future family get togethers will fair.
I told my sister via message what had happened and how I will not stand
for his abuse anymore and forwarded her the logs. I apologized for not
keeping her informed about the conversations we had along the way, but I
thought at the time it was best to focus on what information I could
give him to help her.
Does anyone have any advice on how to deal with such a volatile situation?