While the technology on this planet is surprisingly backward, Google is a very useful tool.
[Filtered To Quill And Mantis]
Quill, despite what you told me about it being "impossible to locate one person out of seven billion", a five minute internet search was able to help me locate your grandfather's address.
Apparently, he and your grandmother are still living in the same home that they had when you were younger. According to this "Facebook", they appear to be in excellent health.
Now. When would be a good time to visit them? Should we call ahead? Given their advanced age, I wouldn't want to shock them too much.
And no, Quill, once again, you have no say in this. We're going to see your grandparents.
Though we should maybe convince Drax that he needs to wear a shirt when we go.