My sister’s husband has been diagnosed in the past (I think) with Narcissistic Personality Disorder. I say “I think” because she hasn’t actually discussed it with me, but she has mentioned it in a past phone conversation. I think he also has Histrionic Personality Disorder. Yes, I am self-diagnosing him, but I don’t have any choice.

That is not why I’m writing, however. I’m writing because I just need some tips on getting through the holidays with him. I love my sister, and her children (she has an older one from a past marriage) and I am willing to deal with his behavior at holidays in order to spend the holidays with them.

These are the behaviors I need some advice on dealing with. Not to treat, not to fix, but just what can I do to minimize the misery.
- He dominates every conversation, talking over other people and insisting on his point of view. He does this even for conversations he knows next to nothing about, and when knowledgeable people are in the room.
- He steers topics back to bragging about his accomplishments. Especially hard to take since he is the least accomplished person there.
- He inflates the smallest compliment he receives out in the workplace (statements other people would not even deem worthy of mentioning) into a long story about how superior he is to the people he works with.
- He drinks a LOT. If anyone brings beer or wine, he drinks the majority of it and asks if there is more, even though he brings nothing. He has always been a freeloader, but that’s especially apparent when it comes to the alcohol.
- He doesn’t really cook, but my sister asks him to make something simple to contribute, as we all traditionally make something. Then we are all treated to a blow-by-blow description of how he made whatever it is he made, and how difficult it was, and how he had to deal with not having the right ingredients because she didn’t buy them. For something like deviled eggs. And then we are not allowed to try it until the actually dinner, and he does a big unveiling, and finally allows people to taste his dish.
- He is a terrible arguer. He resorts to personal insults if you don’t agree with all of his points, and he brings his points up over and over again, even hours later, in a sarcastic tone. He can’t let anything go. It’s like arguing with a ten-year old.

No one in the family likes him. We all just endure his company so we can be with my sister and her kids. We don’t have a big family, so it’s difficult to avoid him at these gatherings. It is basically just 7 people there -- me, my husband, my mom, and my sister’s family (him, her, and the two kids). I know my sister is exhausted from dealing with him, but she won’t talk about it with any of us. At Thanksgiving, she went to bed with the baby at 7 PM and the rest of us had to deal with him all night.

I know they have had some conversations with him about his behavior, because I have overheard her taking him aside and whispering, “Inappropriate.”

We have tried ignoring him, but that just seems to escalate him.

Oh, and in the middle of all of this, he usually has at least one conversation with each of us about how wonderful it is to be accepted by a family, that he didn’t have these kinds of family gatherings growing up, and how much he loves my sister and how lucky he is to get to be “her man” and they are soul mates.

She has decided to stay with him, I think, until their child is old enough to go to school. She doesn’t talk about their problems with me, I think she is embarrassed, or maybe worried about my mom hearing about it from me. I can tell she is unhappy, but she won’t talk about it. I want to support her, and I also want to keep my own sanity and maybe enjoy the holidays a little.

Any tips and techniques would be appreciated.