I wonder how talking to spirit Kevin would have worked if Dean had to have a pottery scene like Demi Moore in Ghost. Guess there would have been more clay.
Supernatural Season 9 Episode 14 sent the Winchesters on a ghost mystery after Kevin returned asking for the brothers to find his mother.
And, yes, on Supernatural, dead doesn’t mean dead, but often a returning character can feel wasted (like Garth in Supernatural Season 9 Episode 12) rather than poignant.
Thankfully, Kevin’s reappearance in flickering spiritual form was more meaningful than just a chance to see the AP student/prophet again.