Fujoshi

So, yep, Yoen dated Vince just because Aryka loved him. Basically, it's his way of showing that he is the "best" (my ass), he is "successful" in everything (also my ass). But parents also have something in it. Maybe he dated Vince because he could use it against Aryka, telling parents that he is only dating Vince because he wants to protect Aryka, or will get reaction out of them saying your son wanted him first so you can't blame me for being gay, or he just wants them to care and try to degay him (because he told Vince whatever he does his foster parents don't care,they just want him to study.)

So, as we know, people who become dream watcher or reapers (doesn't matter) are all in their original forms. Meaning, Aryka used to be blonde, he even had a flashback of his blonde self in chapter 43.
So back to chapter 26 Yoen clearly tells Vince that he is adopted. Meaning, he definitely is Aryka's not blood related brother.
Forward to chapter 30 you can see someone lying on the bed, and a person closing the door while wearing a mask. Who I believe is Yoen, and the dead person is Aryka. Since Vince couldn't get himself to look at the dead person, he didn't know.And because Yoen wore a mask(on purpose) he clearly though it was Aryka and the dead one is Yoen.
And in chapter 34 we can see before an argument Aryka was pretty close with Vince.
I think Aryka changed his hair colour, and wore a mask to school, to "fit in". In other way, he could have wanted to look more like Yoen.
On the other hand Yoen was jealous and he told Vince something definitely wrong about Aryka, like he is homophobic or he told something to parents kinda stuff.
In the conclusion, Arkya died, either because his health problems or because of Yoen (which is more believable for me). After Aryka's death,Yoen changed school, or went abroad. And Vince doesn't remember Aryka because he has seen in only once, in their argument,where Aryka's mask is open.
(Another thing is, I dont feel like Aryka is dead at all. He might be in a vegetative state, and Yoen is abroad, building a career for Aryka under his name. He might have promised his parents to do well under his name, and in the end parents would give him money or anything like that.
Also about the card that declined, like the one who is supposed to be dead, could also belong to Aryka. He is supposed to,but he's not. And the shaman preference is about Vince
I definitely hope he isn't dead and they can get back together)
(PS. I think card belongs to Vince, as the spirit looks more like Aryka. And I hope In the end card glitching will be solved, meaning Vince will be dead, and Aryka too, he will be dismissed as Dream Watcher, and they both reincarnate.)
/If only I could write my homework with this much love and interest TvT /