Responses

I agree 100%!!! Specially after seeing his inner thoughts right after his talk with Mafuyu. He gave me young Akihiko vibes which can be both good or bad depending on what he does truly... hopefully this time around it'll turn out good. I wouldn't want him and Hiiragi to suffer like Akihiko and Ugetsu did :(
Can we take a step back and appreciate Shizu's character?
Not only is he the perfect character to give insight to Yuki, Hiiragi and Mafuyu as a whole (since he's a childhood friend as well) but he's also in the perfect position to give an unbiased opinion of Yuki (as he liked Yuki as a friend, but didn't particularly idolized him or loved him like Hiiragi or Mafuyu in this case) so his character is probably one of the strongest (like he has a strong stance) in this whole arc.
He can see things from inside and outside, and his personality is straightforward and reserved at the same time. He doesn't say much, but he says what needs to be said. He became my favorite character in a single chapter. He voiced what everyone was too afraid or felt they couldn't tell Mafuyu, without sugarcoating it. He wasn't rude, but he didn't try putting it nice either. Brilliant, truly.
Now, what he said was very true indeed. Mafuyu might be wavering not because he doesn't want to go pro but continuing with the band equals something to having the resolve to stay with Ue from now on. If he had any doubts about their relationship at any poin and they were to break up once they had debuted, the band would definitely split and that would be it. Same goes for Haruki and Akihiko though, but let's focus on Mafuyu and Ue for now. Mafuyu really needs to take time to himself, set his priorities straight, and decide wether he wants to move forward with his life WITH Ue in it or not. Pretty much.