Responses
I think he was trying to say that if he believed and his friends and died nonetheless, his mother would've been right and she could laugh at him. But if he survived after believing in his friends, he would have been right in thinking friends are more important than money, and that was proven in the fact that he survived because they chose to give him the treatment.
I am not quite satisfied with the ending i feel like they half-assed it we couldn't get answers to so many questions and what was yuichi exactly trying to say in the last panel? And yuka was a bitch all along? And yuichi was so smart so how could he not realise that the doctor and his mother were lying the whole time?