What was the original problem? And what did he do to try to fix it?
If it won't open at all I would assume the control rods are improperly connected, or not connected at all. Or the latch could be bad. Pull the interior door panel off and check all of the rods that run to the latch and to the handles, make sure to check both ends. make sure the plastic clips that hold them in are in one piece, and that they are all properly fastened. and make sure the rod from the door lock isn't bent or improperly attached. Check the lock levers on the latch to make sure none of them are stuck, make sure they are in the unlocked position. If they are moving, find the rod that runs from the outside handle and push the lever on the latch that it attaches to by hand, if it pops open from that lever you likely have a bad or disconnected handle. If not, have someone lift upward on the door from the outside, if the latch is stuck due to pressure from bad door pins this may let you release it. If none of the levers on the latch will release it, try pushing or pulling on the door while pushing the levers. If that still will not un-stick the mechanism, start taking the latch apart until you can get enough parts out to release it, and go get a new latch.