Aside from needing to get a new hanger for the RD - not cheap - you also have to consider parts should the bottom-bracket need work. It's French - and French threaded BB's are not easy to replace. It will be a PITA. I'd respect my brother by hanging it, as is, in a place of prominence & respect. And get another bike/frame to work with. One that hasn't been butchered by some twit who would likely also butcher a Cinelli.