
Try http://www.mangago.zone/read-manga/birthday/
it's shounen ai but it's so moving - I fucking cried and that doesn't happen so often

http://www.mangago.zone/read-manga/bokutachi_futari_ga_koisuru_riyuu/
Prepare to die inside.

And this one is good. It sort of has a happy ending.
http://www.mangago.zone/read-manga/senaka_kara_daite/an/senaka-kara-daite-chapter-6.html/7/
There's also a chapter in Love Mode. I'd have to check which one, though.
This one has a happy ending.
http://www.mangago.zone/read-manga/kare_no_niwa_ni_saku_hana/
I want a romantic yaoi manga where one of the couple is seriously sick/ill ....and it would move my heart