Is the Therme Parka warm enough for a real winter?

Yes for most city winters. Goose down plus Coreloft and a windproof shell handle freezing temperatures, especially with a midlayer. For deep cold or long static time outdoors, size up to layer.

Is it waterproof or just water-resistant?

It is waterproof. The GORE-TEX ePE membrane is fully waterproof and windproof, and the seams are sealed. It is not a rain shell substitute for heavy exertion, but it handles rain and wet snow.

It has a regular fit with a long, hip-covering cut. It runs trim through the chest and shoulders, so if you plan to wear a thick sweater, consider one size up.

How should I care for the down?

Wash it rarely, with a down-specific cleaner, and tumble dry low with dryer balls to restore loft. Avoid fabric softener and dry cleaning, which can strip the down and the membrane.