How did he get the disease? Sharing fluids with a sick person? Something about this doesn't make sense. If you can't get this from someone who isn't showing symptoms, there must be a lot of people sharing body fluids with Ebola patients in Africa.
Infected person is relatively safe while no symptoms have been developed. However, infection through blood transfusion or sexual intercourse is still possible.
All you need to do if swap bodily fluids, it does not need to be as much as you would get from sex or a blood transfusion. It can be as little as a little bit of blood, vomit or feces
There was a documented case of transmission via a person stealing an infected person's cell phone.
This is possible however in order for this to happen the cell phone would have needed to have blood, spit (not 100% sure on this), snot, tears, sweat (probably most likely) or something similar from the infected person, then the other person would need to get this bodily fluid into their own body (maybe by rubbing their eye). I would say that this would be very unusual and would not be unsafe to use the same cell phone as someone who is infected