For some reason I'm guessing a bug even with the newest patch. Dr. Li will not finish the trip to citadel with me. I looked it up online and it said garza needed medical help or something like that. However, it never said anything like that while I was playing. Anyone else have this problem and know how to fix it.

I'd just reload from the beginning if you can. That quest is legendary for its silly bugs.

My favourite one was when Dogmeat just decided to pop into the sewer and follow me around.

save often. so far that hasn't happen to me but i have heard several here have the same problem. so far far i haven't heard of anything that can get that quest back on track.

You could go back to where Garza has stopped and kill him. She should move her behind then.