A childhood belief about afterlife

When I was young, my great-grandfather died and "went to heaven," according to my mother.

Then, at most a year later, my dog died. My brother was asking my mom if the dog was in heaven. At this point, we were driving past an apartment complex set up on a hill and surrounded by trees. my mom responded, "Yeah, Sheba's in Heaven with Pampi," while gesturing towards the sky, but I thought she was pointing to the apartment complex... and I thought for the longest time that Heaven was in that apartment complex on the hill surrounded by trees. I couldnt' understand why, if they were right there,why they just couldn't come home.