Ghost Playing A Trick On My Grandfather?

So I didn't actually expieirence this haunting event, but my grandfather sure did! (I will try my best to describe what I heard from my grandfather.) It is around 30 or more years ago and a sweet old man dies of a heart attack at his home. (My uncle was actually the one to find his body and report it to the police.)

(Fast forward some years)

My grandmother's parents buy the house that that sweet old man lived in, and they hire my grandfather to renovate/work on their house and get it ready for them to move in.

One night, my grandfather is waiting for his friend (let's say his friends name is Brad, because I don't remember his real name) to come and help him work on the house.

All of the sudden, my grandfather hears loud footsteps in front porch of the house. (Being a very humorous man, my grandfather plays tricks on his friends all the time) So, my grandfather thought his friend Brad was playing a trick on him. "I know that's you, Brad!" My grandfather shouts. There is no response, so my grandfather walks over to the front porch and opens the door. Right as he opens the door, a HUGE rush of coldness rushes through him, and all the hairs on his arms stand up. My grandfather quickly closed the door, packed up his tools, and went home!

(Later that night)

My grandfather is cutting wood in his basement (at his own home) when my grandmother comes downstairs. "Honey, are you alright?" She asks. "Your face is so white, it looks like you've seen a ghost!"

Yes, it could have been the sweet old man's ghost playing a trick on my grandfather. But I'm not sure! Any ideas? Comment!

~Thanks for reading!~