So, enter the bittersweet reunion. No, he didn't forgive Sam. He put his brother through the ringer instead.
After all, despite his intentions, Sam did the unthinkable. He betrayed him for a demon. Dean tried to see past it and focus on task but the hurt was too deep and the betrayal too raw. He couldn't forgive.
Dean appears visibly saddened by Castiel's lack of faith in him. Castiel later returns in Two Minutes to Midnight and apologizes to Dean for not having more faith in him. Dean forgives Cass, and they reconcile.
This meant that viewers got minimal details about Sam's life after Dean died in the Supernatural series finale. In Sam's old age, the Impala can be seen under a sheet, implying that he stopped hunting.
At the same time, some fans were perturbed that Dean did not reciprocate the feelings, as this implied Castiel's love had been unrequited for all these years. Many were also upset that following the declaration, Castiel was pulled into the Empty which is where angels go when they die.
On multiple occasions, Dean has shown that - of all the women he has slept with - he truly loves Lisa. Before and during the first few episodes of, season 6, Dean lives with the Braedens for a full year, living an "Apple Pie" life. Dean's nickname for Lisa is "Lis'".
The phrase “I love you” is used forty-eight times in Supernatural between episode 1x01 and 8x08. Only four of those come from Sam or Dean. Only three of those are from real people directed to Sam and Dean.
Eileen Leahy - Sam's final love (Season 15)
That is until Chuck wiped everyone from existence (“Despair”).
“Goodbye, Sam” are Dean's final words as his hand drops and a tear rolls down his cheek.
A Lackluster Plot
Supernatural boldly chose to forego the usual TV finale format - virtually every plot thread was already tied off in the penultimate episode, leaving one final hour to focus entirely on Sam and Dean Winchester. In theory, this made sense.
When Dean died, he left Sam alone, and he hasn't quite forgiven himself for that. Though we know that Sam is okay (he eventually marries and has a son, whom he names Dean in honor of his late brother), Dean is still the over-protective big brother he's always been.
However, his affection for Castiel ultimately won, with Dean shown in tears in Purgatory when he thought he'd lost Castiel. Their reunion was their most intimate yet, as the two didn't hold back on letting the other know that they were truly sorry and didn't want to fight anymore.
In the end, Dean (Jensen Ackles) went out the way he always thought he would: Hunting. He was killed in the series finale while taking on a nest of vampires, but his ultimate end would come in the show's final moments, when he was reunited with Sam (Jared Padalecki) in heaven.
After going to Heaven, Dean is impressed and proud of the changes that Jack has made. Bobby Singer calls Jack Dean's kid while they talk and Dean doesn't say anything to the contrary, suggesting that Dean ultimately forgave Jack and came to see the young Nephilim as his family again.
Power: Dean
Even if Sam is taller and generally seems more fit, Dean has demonstrated on many occasions that he's the more powerful of the Winchester brothers.
Season 3. While trying to cope with his impending death and make the best of his final year, Dean begins to start hunting the freed Demons. Meeting a seemingly helpful demon Ruby, Dean learns that he too may become a demon himself if he burns in Hell too long.
Dean later briefly possessed a pair of Black Eyes while he was a Demon. Since separating from Sam, his appearance has become more scruffy and unshaven; his hair has also grown out a bit. In Let the Good Times Roll, Dean gains a pair of Angel's Wings due to his status as Apocalypse World Michael's current vessel.
"I cared about the whole world because of you. You changed me, Dean,” Cas added, before saying "I love you," and achieving his moment of happiness, thus ushering in The Empty to absorb both himself and Billie, sparing Dean's life in the process.
Before dying, John tells Dean, if he can't save Sam, he'll have to kill him, should he become evil. The fourth season episode "On the Head of a Pin" reveals that the demon Alastair tortured John in Hell for over a century, with John refusing the demon's offer to stop if he himself would torture someone else.
Fitting: Ended Up In Heaven
Most fans know that whenever a person dies, they either go to Heaven or Hell. Because Dean died several times in the show, it was only fitting that he not only died in the show's finale but that he was rewarded for his job as a hunter by going to Heaven.
The most obvious reason why Castiel would gravitate more towards Dean than Sam is because the elder Winchester brother was his mission and his reason for coming to Earth. In the Supernatural season 3 finale, Dean dies and goes to Hell, presumably for good.
The easiest way to handle all that was to avoid as many people on set as possible. That meant skipping a lot of the past characters, including Castiel. Misha Collins, like the others, lives in the States. He would have come to Canada and quarantined for two weeks.
Cass reveals that he has learned a lot about being human and reveals he had sex with April, leading the Winchester's to be surprised. Dean even goes onto make a joke about "having protection." Castiel goes to eat and Ezekiel takes over Sam saying Cass can't stay because he will bring the angels down on them.
Dean had no reason to say something like that to Cas, of all people. This is the response I get. Or, so Jensen just wants to stay true to Dean's character.
Dean is very protective towards the people he loves. Be it Sam, Lisa, Ben or anyone else. Dean is the character which is the most betrayed. So people tend to go more towards him.