This story comes from my dad, who told me this when I was 12, I was highly interested in anything paranormal and although this probably pales in comparison to other stories on here, I think it's still interesting considering it happened after a funeral.
This takes place before I or my brother was born. Just to set the scene, it's an apartment on the bottom level with a side door that is the main entrance, but it has two floors. Anyway, my mom and dad were coming home from my grandpa's funeral, and as they were unlocking the door they heard a lot of footsteps from the second floor. My mom and dad looked at each other and quickly unlocked the door and ran in. They searched the whole place, 1st and 2nd floor found nothing. Nothing was disturbed. No one in the house. The only alive thing in the house at the time was the cat, and my dad says it distinctly sounded like footsteps. My mom, who's never really believed in ghosts, told me it was the cat knocking stuff over (though according to my dad nothing was touched or out of order) and my dad likes to entertain the idea it was my grandpa visiting them one last time.
I personally like my dad's version, but I wasn't there and I technically got two versions of the story. My mom looked at the situation reasonably and with most logic, however because they were coming home from the funeral I like to believe my grandfather was doing a final walk-through. I'll probably never know, and frankly I don't even think my parents think much of it.
Your dad says that everything was in place, does your mom agree with him on that detail? It's always good to seek out a logical explanation, however sometimes there are incidents that defy and lack any sort of reasoning and logic.
So I will have to agree with you and your dad, that perhaps your grandad did come to visit for a last time.