A friend of mine is replacing the timing belt on a 99 Nissan Quest (109k
miles).  He made sure it was at TDC, distributor points to the #1 cylinder,
and the crank and the Right-hand cam sprocket are lined up with the marks.
He replaced the water pump and was putting on the new belt and noticed that
the belt had two marks that lined up with the crank and the RH Cam sprocket
marks (and also lined up with the bumps on the metal back plate in front of
the engine block, but for the Left Cam sprocket there were some arrows
(>>>>>>>> I don't recall the direction he drew out).

The can sprockets do NOT turn freely - not even with a wrench!

He put the new belt on and was checking things over.
Problem is, the left sprocket (which he can only see with a mirror) is not
lined up.  Instead of being about "11 o-clock" per the picture in the manual
and the little bump on the metal back plate, it is apparently about "1
o-clock" or so.  But the engine ran fine before.

So: Question 1: Is this a negative clearance engine (i.e. if the valve
timing is off, will the valves hit the pistons)?
     Question 2: Any idea why the sprocket (or the whole cam timing) is
apparently so far off, and how could it have been that way when he can't
even turn either camshaft?

    He has replaced lots of timing belts, done engine replacement on his
Volvo, etc.  He is trying to help out a widow who is a friend of the family.
He doesn't want to damage her van in the process.  He already replaced a
leaky hose hidden under the intake on top of the engine, but figured with
that many miles on the car, the water pump and timing belt should also be
replaced.

   Any help would be highly appreciated.