This probably won't help but it is the truth. I didn't have a relationship with any of my grandparents growing up because of various reasons, none of which were estrangement. However, I think parents "give" their children grandparents and if they don't children may just never feel that connection or interest. I feel a connection to the family line on my dad's side just because he use to say your grandma this and your granddad that. My mum, on the other hand, use to talk about her parents by saying her mum that and her dad that. The content of what they said about them didn't matter. Just the name they gave them and whether they talked about them as theirs or mine. When my dad died I traced his family tree. But I have never felt that my mum's parents were anything to do with me. Even today I can easily refer to Grandma (insert next name) but I stumble over calling the other set of grandparents anything other than my mum's mum or my mum's dad.