Sorry to hear of your trouble, and it sounds like a puzzle.
A word of caution; I understand that if there is an internal leak where engine oil can get into the combustion chambers, it can cause a "runaway" in a diesel! I have heard of this happening in stationary engines, so I suppose it could happen in a car.
The engine doesn't care whether you inject diesel fuel, or motor oil, and since the motor oil leak is NOT controlled, you get as much power out as you put oil in, ready or not!
I'd advise you proceed really carefully, up to and including having it towed to a technician for a better look.
'96 E300D 60k mi (wife's daily ride)
'95 Audi 90 118k mi (for sale)
'92 GMC Suburban 138k mi
'85 300SD 231k mi (my daily ride)