The MC was such a shitty ireedmable person he didn't deserve a "good" ending nor did he deserve the love of the father after what he did to the son. It was obvious the father had reach a point of no return once he made the choice to adopt the MC out of revenge.
Well the ending is.....its alright(〜 ̄△ ̄)〜
Its not a bad ending, its not a good ending either....its just normal??( ̄∇ ̄")