Riggie: I can't really say too much about what your friend may have done to the turbo, but having rebuilt turbo's myself i can assure you 101% there is seals inside, and even a "minor" turbo service kit includes them.

The seapage you have currently is because the turbo has been filled with oil and isnt on a running engine, the oil seals in turbos rely largely on simple physics laws to control the oil within the turbo. Those marks on the compressor turbine looks serious in the pictures, are they actually worn?