that is very strange to hear a lobe to wear out . make sure he has the right fuel pump, most fords take the same fuel pump gasket and you can bolt the wrong pump to the engine , (lobe is in a different spot)  or you might have a bad new pump,  pull it off and match the old one that use to work to make sure , the arm has to have the same shape as the old one , if not it came off a different engine , hope this helps

That's odd never seen one wear out but easy to change , do not know if you can do the work your self or have to get someone else to do it , you have to remove the timing cover and belt to get to the shaft , you remove the distributor, fuel pump and then the timing belt sprocket, the the three little bolts , remove the cover and you see a plate with two screws , remove them and shaft will come out , not hard at all, but first I would make sure the lobe is really gone before you do this for nothing, remove pump and use a smart phone and take a few photos and post , turn the engine to see all sides of the lobe , and last is make sure the timing belt is good , they ether brake in half or sheer the rubber teeth off on the crank sprocket, then the engine will not run , no fuel pump, distributor or oil pump , all driven by that shaft , good luck , later Blaine