When you want to see one parent but both of them come as a unit

How do people approach longing to see one parent but being unable to because the parent they hate/dislike will have to be involved as well?

My dad failed me as much as my mother in many ways but he was certainly nowhere near as cruel verbally and he was never physically abusive, unlike her. He also never directly put my life in danger as she did, but he did often cover up the damage. I still care for him, despite knowing this, but I never want to see my mother again.

He has told me that he's ill (I listened to an otherwise blocked phone message) but I never want to return to see the rest of my family ever again (three siblings and my mother). They come as a unit, as I said above. The boundaries and trust is simply not there for me that I wouldn't be treated like shit and shouted at by mother for not seeing her (she doesn't actually care - she just wants a reason to shout).

Am I being cruel? I'd be ashamed to tell anyone that I didn't see my father even though I know my history would make it excusable/acceptable.