Non-BPD with possible BPD sis-in-law..questions?

This is my first post so I do not know if I am doing this right. I am non-BPD with a possible BPD sister-in-law. I am concerned about her well being. For many years, I thought her behavior towards me was very disrespectful but now I am seeing that there may be something more going on.

She has always tried to shut me out of events or conversations that involved her father or brother(my husband) and has had a very hard tome accepting our marriage. She will constantly say things like "this is my brother" " I used to be his number one girl" and I thought she just looked up to him as a younger sister. She is 30 yr old and he is 36yrs old. She also punched me once in the arm when I said something as a joke that she percieved as criticism. I was really taken back and let it go.

This past weekend she came to visit... she lives in another state. Well, her abandonment issues seemed to be more severe than in the past. *** Sensitive content*** her boyfriend committed suicide 6 months ago and after about 1 month, she stopped talking about it and everyone in her family did also. They said that she was doing great, which she wasn't. **end of sensitive content**

So, when she was here, she was extremely attached to my husband. She will even go as far as to push me out of the way to get closer to her brother (my husband) I felt like she was marking her territory in my house and I am guilty of getting involved in "turf war games" with her because I was trying to set boundaries.

For example, I have a favorite seat on my couch where I put my space heater on, use my snuggie.. , and cuddle up with coffee and watch TV. I had mentioned that I like doing this and when she was just visiting, every morning after I mentioned this, I would wake up and she would be out on the couch with my blanket, space heater and coffee in that spot.
It felt strange to me. It almost seemed as though she only felt comfortable near my husband or taking over my "role" in the house while she was here. And it seemed like she did not have any idea about boundaries. My first inclination was to get angry that she was taking my space but then I saw that there was something more going on.

She will mock me when over things when she is sober as if I am her enemy but when she is drunk (which happened alot, I think there is a problem) she was very nice to me and much easier to be around. She seemed to have let down a guard. She also has an excessive laughing thing where she laughs at everything whether it is intended to be funny or not. Her mom mentioned that this is worse when she is nervous. Someone at a resturant even told her to stop because it was so loud and distracting. She did not seem to notice.

I guess my question is, does this sound like BPD? How can we set boundaries in the future?

Thank you.

It sounds odd. Who knows if it's bpd or not. A second hand account of someone acting strangely after their boyfriend killed himself...........

How can you set boundaries? Well.......have a non-emotional business type discussion and make the rules clear and enforce them. The key, is CLEAR and ENFORCEMENT. If you waiver on either......then you're in for a hard time.




What does your hubby say about all this?

How often do you see her? Is it worth the fuss?

Thank you for your response. My husband is concerned and not sure what to do or how he can help. She needs professional help and I do not think that she would respond well to him telling her this. So he just tries to lead by example when she is around.

Thanks for the boundary tips, I will try this. We are not around her too often so I think I will just wait until next time and take it as it comes.

I guess I am just trying to make sense of her behavior and get as much info as possible because it is:
#1. worrisome and #2. very innappropriate