2008 BMW 128i Timing belt broke w/84k miles, my mechanic said is no worth to fix it,

I took my wife's BMW for an oil change. The next day the oil level was zero. I
took it back to the mechanic 2 miles away, it stopped right at the entance and
couldn't restart the engine. It needed to push. Later he called me ,timing belt
broke and it is not worth to fix it with a new or used motor. I told him that I
found big oil spill on the ground where my wife parked the car after the oil
change. Do you think this oil leak would cause the belt to break? Thanks
Percy