Responses
Yes, the purpose to come back to his world is to continue to live for his mother.
If he decided to continue in the Titan world then his existence in his world is long forgotten. Hence the sacrifices and death of his mother will be all in vain. (Koichis point of view)
So I get that he has people he cares about in his world. However, the reason of him returning in this chapter confuses me. His mom died because she wanted to save/give him the best life right? So it doesn't matter if he comes back or not, as long as he is alive, her sacrifice is not in vain. Is he coming back to his own world to give the meaning for his mom's death ?