How could he tell Katrina that he'd found her grave?

She went into the churchyard and found their parents' grave.

I feel silly trying to find his grave with no guidance.

I have gone there, but I could not find his grave.

Years later, the boy tries to find her grave, but it no longer exists.

There seemed no way that he might find the old man's grave.

We also failed to find his grave and there was nobody about to ask.

Detailed instructions to find his grave can be found here.

Be careful you don't find your own grave before this night's done!

As a result, she is able to find and visit her father's grave in Haifa.