I have an 97 A6 that has been draining coolant. A mechanic told me that it is the water pump which is scheduled to be replaced tomorrow. However, the heater has suddenly stopped heating. Are the two (wp and heater core) inter-connected or is this a stange coinsidence?

 

yes they are interconnected as the wp circulates the coolant through the engine and the heater core. no circulation no hot water

You WP must be really bad. Don't start that engine anymore.
Tow it!

If that WP fails and the belt slips off your valves are toast.
I would have him replace the Timing belt while he's at it, since he's removing it anyway.