My sweet post-canon Dean. He is 42, and 43, and 45, suddenly. And more. And he is still alive — It has a fine line between insanity, punishment, and great gift. Dean isn't sure who to thank (and who to fuck off, first of all)
Without a sense of constantly looming danger, this is a little unusual, but he keeps his fight. And, if we talk about the happy part, not that one where he spends most of the time in dissociation and anxiety, he gains weight. Because therapy requires sacrifice (especially if you were almost stabbed to death in a barn a few months ago, Dean. Do you know that getting fat is not prohibited by law? I know, I studied to be a lawyer. Live your American dream of a perfect wife from the fifties. And take your damn pills. Well, Sam is usually a little less harsh, but, you know, caring sometimes shows its teeth).
Dean doesn't know why this brings him to tears. Maybe this is a new life after death, and he has become a teenage girl. But actually, it's much deeper than his waist, thighs and ass.
He is chronically, painfully useless. He's no longer a hunter, he's no longer a Winchester, he's Dean. A Shell that collects fragments of something long broken inside itself, like a Frankenstein monster sewing itself together piece by piece. Melodramatic? A little bit. Sue him, he has a lawyer.
Dean takes pills, cooks, cleans, cries and sleeps. For Sammy, for his dammed psychiatrist and psychologist, for little Dean, who has always dreamed of being big enough to cover Sam with his body.
Getting fat is just... not in his character, because now he is more alive than ever. And this is not Chuck's plot, not a war between Heaven and Hell, it's a life, where the Shell takes shape. Dean realizes that he still has years of therapy before a "normal" life, but if "normal" life exists at all — or if he finally finds a Normal Life For Himself — he's ready to rack up another extra fifty pounds.
He eats, cries more (seriously, when is it over, he should have lost weight after all the tears he shed), cleans up more. He can cover Sammy with his body (probably?). He can take pills and look at himself in the mirror with almost no hostility.
Perhaps at night, before going to bed, he examines his body, confuses stretch marks and scars on the lower part of his belly, touching the softness around the navel. Being soft is strange (especially in the chest area, okay? A midlife crisis doesn't have to mean suddenly grown titties, there's nothing sexy about it. Though... oh stop wait forget it). Still not in his character. Sharp and sick character named Dean Winchester. But maybe Teenage Girl American Ideal Wifey Dean Who Cooks Eats Takes Pills For His Fucking Sammy And His Fucking Therapists And His Fucking Future deserves all the pounds he has gained. Who knows. As usual, this is too melodramatic. Sue him.