Your point of view of percepting the story is quite intriguing!
After reading the entire story, I got the impression that alec is finally free like he's supposed to according to soho.
Abt your last sentence, I didn't think that was the case, I'm sure it more inclined to soho could finally "love" alec bcs he's the same as him now, bcs he killed his father. Though soho might not love him the way true love is, it's more like caring & catering to alec's needs and wants.
The author didn't show soho in the last part was maybe bcs they wanted to portray alec's freedom, that he's truly free now, he's smiling in pure bliss. This could also meant like symbolism or implicitly telling that they're really together & "love" each other now with that couple hugging on TV. Bcs seeing the couple on TV was more like, you know- "finally we could be together happily ever after" wtv typa shit.
Also, I recalled soho finally embraced alec first when he showed his parents' graves.
I tried to understand the plot and so on. (Correct me if I am wrong)
From the title “Nest.” so it's where birds lay their eggs. In my perspective, it's very likely to have a few similarities but instead the negative side of this nest. Nest in metaphor describe as home, but instead of alec's home are filled with toxicity and abuse. Warm and comforting environment—in fact on what I noticed, only Alec's comfort and ‘warm environment’ is Soho that what i noticed Alec become dependent (something) to soho's environment.
Eventually, yeah Alec kills his father and he publically viewed to everyone that his father attempted suicide. In the end, we could see two couples hugging each other and we couldn't find Soho. So I theorize that Soho may actually be alive. Plus the man couple from the television was not showing his face, so meaning that the one who embraced the reality is Alec himself.
Oh plus that meaning yeah! In poetry, if there's two person arr hugging but one is not, there's unequal love (Alec loves soho deeply while soho doesn't)