Yeah the normal thing would have been to start with supervised visits then after you get to know your kid ask the brother if he's willing for you all to live together. In no world is a child going to do well with being ripped away from the only parental figure they have ever had. It's obviously that wanting his kid back is about his own selfish needs and has nothing to do with actual love for the child.
This absolutely. Plus at this point the brothers are a package, they grew up together. Separating them is of no use and will only do harm.
Big bro doesn't even have to be a child, and he and the father don't even have to be blood related. These two are brothers, and the only way you're getting back in their life as a father figure is to be a father to them both.
Plus, in the story we can see clearly big bro could really use a parental figure/someone to take care of him financially. He could really use a home to fall back on -- and that's something this guy should be providing. Shame on him for only being willing to take care of the little guy-- and being completely willing to traumatize him in the process.

Dad dude is so entitled. You let your kid get raised by his brother and then only take in one of the two. Any sane person who wants to mend this sort of gap would have the sense to take care of both of them to even REMOTELY make up for the lost time.
If anything it would've been a better result than letting them both get taken care of by this psycho (sorry big alpha manchild don't think I forgot)