The water pump Does have a drilling in the casing between the two bearings.
If water is coming out of this drilling it means the seal on the bearing has
failed. This will be followed by the bearing failing in time.
The fuel smell in the heater is probably from a leak in the engine bay.
Suggest you get the injection system checked out. If the engine is running
rich, you wouldn't smell it. You only smell neat fuel. Again, suspect
something is leaking.

Some cars' waterpumps drip a bit as an indication (warning) of a worn
seal. My experience with M-B water pumps (on diesels) is: perfect one
day and a gushing leak the next.

Fuel odor is from a leak on the engine. It won't "go away" so have
someone fix it.

The engine running "too rich" may be related to the fuel leak - or not.
Either way, the air / fuel ratio can be adjusted by a trained M-B mechanic.