Does DBT work if the pwBPD doesn't know they have BPD?

[Littleleft]

My SO seems to have BPD. One of the psychiatrists he's been seeing says he is 'emotionally unstable by personality' and I think that's what he's saying without wanting to give the label (not just from that sentence but from other things he said too).

He's being referred to see a psychotherapist. He's not keen (which worries me) because one of the psychiatrists he's seen at the same mental health clinic is taking him off some meds (clonazepam, a benzo like Valium/diazepam). They're probably right to do that because he is using it like a crutch (as he has done with alcohol in the past - now in recovery- but continues to do with smoking weed).  He thinks only his sponsor can help him, because in his opinion his problems now are from being a dry drunk.

I think they will offer DBT, but was wondering how effective that can be if the person being treated doesn't know they have BPD and therefore doesn't realise the way in which is affects the .  Does anyone have any experience of someone having DBT when they don't realise they have BPD?