Given the years of their lives, it's unlikely that they were other than blood relatives, but I share your fantasy.

One of the beautiful realities is that, for some time now, more and more gay couples are refusing not just to "kiss in a shadow" but refusing to die in a shadow, too, choosing to be buried side-by-side with shared gravestones [as Getrude Stein & Alice B. Toklas did decades ago in Pere Lachaise in Paris] with inscriptions making their relationships obvious or explicit such as one in DC's Congressional Cemetery that reads:

"William R. MacDonald, Jr.
April 8, 1948 - May 5, 1990

BELOVED SONS AND PARTNERS

R. Michael Sanders, M.D.
July 10, 1947 - Aug 5, 1994"

a photo of which can be seen, along with some other gay gravemarkers, at:

http://leonardmatlovich.com/storyofhisstone.html

I've yet to upload a photo of the most remarkable shared stone there of a gay couple who [according to research I've done] met when they were attending Catholic University in the '50s [one partner is apparently still living]. It's a full-size granite picnic table complete with two benches. On its top is engraved:

"Us

While wondering down the back roads of my mind, I came upon a memory of us, faces garden-fresh, blooming, and full of promise. My inner-eye welled up. Furrows have etched their way into our fields of being. What had Youth’s straightness now bends and curves into accommodation. We have become ourselves not alone but with each other’s help. On the face of it, Youth’s bloom has gone, replaced by hardier stuff whose roots are deep and all encompassing. How fortunate we were to have loved each other then and even more so to still love each other now. Forty-three years together is not enough but we will be together again.

John Andrew Frey
August 29, 1929
August 22, 1997

Peter Louis Morris
December 29, 1929"

My grandmother's gravestone has a nickname on it -- one that she, sadly, didn't much like and which could be mistaken for a man's name.

When I was in high school, our band was in another school building, lining up in the hallway to go into the auditorium to play a concert. It was well known that the students in that building were "special ed." I saw that one of the lockers had my name taped to it and I thought someone was making a sophomoric joke at my expense. But I didn't take the name tag down. I found out soon after that in this small town, someone else had my same unusual name.

Yeah. Oddness. There is someone with my name in my state who runs a heavy duty branch of the FBI. Wonder if I can make use of that . . .