Welcome SunsetRain:Sorry about the situation with your MIL. It has to be frustrating.
How do we ask her to get tested for bpd when she refuses to consider it an option?
You have no power to change her, but you can set personal boundaries around her undesirable behaviors. She has to make her own decision that she wants to get help to modify her behaviors. She either lives with the consequences of her behaviors, or goes for help. The job of you and your partner is to unite in regard to boundaries you will set and enforce.
It would be good to spend some time getting acquainted with some of the communication tools and strategies available here. A good place to start is to go to the "Tools" menu, within the large green band towards the top of the page. A good starting place would be to read about boundaries and Validation/Don't Invalidate
You have to do things that are within your control and set boundaries that you have control over. You can set boundaries in regard to behaviors you are exposed to:
i.e.
- Until MIL is able to demonstrate that she can control her temper, she will not be alone with the baby. (or whatever the issue (s) are)
- If you are at her home & she goes into emotional dysregulation, you can say something like, "We can see you are having a bad day, we are leaving. We will be in touch when you are feeling better."
- If she acts out at your house, you need to ask her to leave, in as kind a way as possible. i.e: We care about you and want you to get help with your emotional control, but we choose to NOT be around you with this behavior. We are asking you to leave. We can get together some other time, when you are calm and we can have a pleasant visit.
What are some of her worst problem behaviors?