This is one of my favorite mangas, so I hope this is really gonna happen.
Seriously, I'm gonna cry no matter if he proposes or not. The difference is just crying for happiness or sadness.
So, Yuuya!!! BE A MAN PLZ!!!
I'm not sure how exactly you five could help Fuutarou with the other 4 wishes, but in order to make him rich, just any of you marry him on his birthday, and he will eventually get rich~ 0w0 b