Soooo... I'm Still Unsure Whether S15x20 Was A Fever Dream Or Not- But One Of The Many Things That Still

Soooo... I'm still unsure whether s15x20 was a fever dream or not- but one of the many things that still baffle me about this episode is the concept of time in heaven?

Alright, get this: Sam starts a family with an anonymous partner (Eileen? Gabriel? With a wig? We'll never know...), they raise a child, Sam grows old, dies of old age. How much time has passed? 40, maybe even 50 years? Right. Ok. Copy that.

In season 4 Dean tells us that four months on earth equal 40 years in hell.

Let's say out of some bizarre reason this rule applies reversedly to heaven... Are you meaning to tell me Dean spent four months driving around heaven in the Impala? Just? Driving? Not seeking out Mary, John or ... *deep breath*... Castiel, his best friend whom he has known for over a decade, who literally sacrificed himself 30 sec after a heartbreaking love declaration in order to save his life, who upon being resurrected immediately participated in reconstructing heaven for his beloved?

Or does time up there pass even quicker? But why has that never been an issue before? Not once have time differences influenced the plot in any way, shape or form. Because it's ridiculous!!! Imagine Cas visiting his angel buddies to ask yet another favour (or stab someone... or both, I guess...) just to realize upon his return that the Winchesters have died of old age because he spent a minute too long above the clouds. Like? What?