So I wonder if we will ever have a truly close relationship or is it just a mother caring about her son. For example he is not going to be part of my medical care (living will) because I cannot trust him to make decisions on my behalf if am unable to. I have not told him this because it would start all sorts of stress but it has to be in place.
I'd say that the reality with untreated BPD is that the relationship is mainly one-sided: all take and no give. Relationships even with treated, stabilized BPD can still feel lopsided. I confess, I have felt much less hurt and disappointment when I maintain extremely low relationship expectations of my BPD stepdaughter. I don't expect any thank yous or sorrys. I don't expect courtesy calls or texts (e.g. if she decides to stand me up for dinner). I don't expect her to show any interest in my life such as asking, How are you? I don't expect her to wish her dad Happy Birthday or Happy Father's Day. My policy is to invite her to Christmas and buy her presents, but if she doesn't show up, I will put the gifts aside, to give her on another occasion or maybe give them to someone else. The reason I do this is because, when she's a no-show, she's tacitly communicating her need for space, and I will respect that. Sometimes she'll be nice and act in a civil manner, and my attitude is, that's a nice change. But history has taught me that with her, things tend to be temporary, and to expect a permanent change is bound to disappoint. The kind way to say this is that it's all she can handle to get through the day, and expecting her to be nice to me or her dad, let alone do something for us, is just beyond her capabilities right now. I'd rather see her focus her finite emotional resources and energy on her own life than "spending" it on doing something nice for her dad or me. It's better for her that way, as there's less emotional baggage getting in her way.
As for something like a living will, the pwBPD in my life wouldn't be an appropriate representative or power of attorney, no way, because she simply cannot think in terms of other people's best interests and their wishes over hers. Moreover, she is overwhelmed by mundane day-to-day affairs; I think she couldn't handle a high-stress, emotionaly-charged, administratively complex situation like end-of-life decision-making on someone else's behalf. I recently went through that situation with my now-deceased father, who succumbed to cancer. The entire ordeal was extremely stressful for me, combining the loss of a parent with the duties of being a living will representative / PoA / executor. For context, I feel I'm generally emotionally tough and very capable when it comes to legal/financial/medical administration/logistical matters, which is probably why my parents chose me for this responsibility over other siblings, though they are very competent as well. There was a point when I made medical and other decisions for my dad (together with my mom), when his periods of lucidity had faded in the last few months of life, and he wasn't deemed competent anymore. In some ways I regret not becoming his proxy (i.e. taking over) earlier, but I didn't have the heart to take away control from him, when he was still "there," at least part of the day--because feeling in control was so important to him. There was a dynamic near the end when my mom couldn't convince him to do what was best for him (e.g. take his medicine, bathe, clean his sores), and I was "the only person he'd listen to"--hence the need for a proxy. Anyway, the whole ordeal wasn't easy, and two years later, I'm still dealing with estate affairs. I think a pwBPD couldn't handle something like that (i.e. act in someone else's best interests and be relied upon to execute the complicated administrative affairs), no way. For context, I'm usually a very healthy person, and after the ordeal I had some health issues (insomnia, rashes, inflammation), which I think was a manifestation of the high stress of the situation, of course combined with issues with my BPD stepdaughter.