Both Sides Now (http://nocturniquette1.livejournal.com/48670.html) is J2, with Jared being diagnosed with leukemia. I haven't read all of it, so I don't know how it ends, but I know the majority of the fic is about Jared's treatment and his relationship with Jensen. Warnings for child sexual abuse and infidelity (I think).

I loved this one: As We Fall (http://archiveofourown.org/works/708425) Jared Padalecki is a high class businessman, Jensen Ackles is a high class prostitute. But this is no pretty woman re-make: When Jensen’s diagnosed with cancer, Jared decides he has to look after Jensen, even if Jensen doesn’t want to be looked after by his former client, and it’s not long before their strictly business relationship becomes very complicated.

http://m.fanfiction.net/s/9329732/1/Flecks-in-the-Sun
Wip but good so far. No slash.