It sounds like you love him very much

How has he dealt with his diagnoses, especially BPD? Keeping things light and fun is a good initial plan. Have you seen the lessons to the right of the board? Understanding what he's going through can help you immensely. Shame is a powerful and debilitating emotion for anyone, but more so for a pwBPD, whose emotions are often uncontrollable, and who think in black and white terms (all good or all bad). Therapy isn't necessarily a panacea because he needs to stick with it. Committed patients, ideally with the support of loved ones, do make progress.
You can encourage and support, but in the end it's his decision to seek treatment and stay with it. This may be a confusing, possibly frightening stage for him. Perhaps this can help:
Anosognosia and Getting a "Borderline" into TreatmentAs for his family, one can't blame them for feeling that way, but neither you nor him are responsible for their feelings. The kindest and most helpful thing for them to do would be to step back and support him, not so much the r/s. Seeing him as a person in psin and validating his feelings is more helpful than telling him how awesome you are (even if it's true

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