My paternal grandfather died before I was born, and my father assigned his given-name to my middle-name to honour his memory.
I could describe him as "my late grandfather" but "late" simply means deceased - I'm wondering if there's a word or short phrase to describe a relative who had a somewhat untimely death (he died in his 60s) that would otherwise have been around to see me grow up.
Basically a more succinct version of "my died-before-I-was-born grandfather".
(Secondarily, should my question say "...that would otherwise have been..." or "...that would have otherwise have been..."? The repetition of "have" seems incorrect, but lacking it also feels incorrect).