This is neither coincidentally funny nor is it heartbreakingly sad. This is the most devastating and soul-crushing action we had to witness in a very long time.
The minute Sam is back he will not only beat himself up for what he has done, no, he will be furious with Dean but mostly he will blame himself for the rest of his life. Just like he always blames himself for everything; for every death he caused, even if it has never been his fault in the first place.
Another layer of guilt Sam Winchester will put on and carry with him. None of this is going to end well and I’m scared of what Kevin’s death will do to Sam.