Wait i dont get it, is the brother khmself? Or just died?

He k-worded himself I'm guessing he got depressed after finding out his brother was dead I mean it makes sense man's was already spiraling when he left for good

I found it quite ambiguous actually, maybe it's a plot point

Really? (This gonna be super long read if you want) I feel like it was pretty clear especially when we got the flashback. What I understood was that he basically saw his brother as his salvation/ savior like he was getting abused by workers in the parlance and his own mother, his father probably had multiple children so he barely got his affection then here come out mv we treats him with love and respect then queue the obsession, which just got worse and worse over time he basically was living for the brother and now that he's gone what does he have to live for? He says it too when he was talking about why it took him so long to come back and find him he was making the country better for him.

yeah, he had reasons to unalive himself, but the way it was shown was not straightforward, but rather ambiguous, with him just wandering into the forest and a witness saying he jumped off the cliff. in this chapter it has already been shown that people gossip without committing to the truth.