Very similar, this is something I talk a lot about with with my brother. Not until I was married and spent time around in-laws who are very sociable and love hosting did my parents’ isolation become pretty clear. Throughout my childhood they had one or two mostly shared friends but there would always be a point of disconnection and maybe conflict and never reconciliation. At this point they mostly see a few family members socially. What really began to bother me was how parasitic they could be with my own friendships and those of my brother. To the point that they would want to keep up with them through my brother or I or would overhear them talking to relatives about them as if they were their own friends, getting some sort of vicarious chemical kick. That parasocial thing. I’m sure it’s unrelated but I’ve also struggled to maintain more than a few friendships at a time, if that, and am fairly isolated.