Yes. DB doesn’t operate any sleeper cars. All sleepers operating in Germany are by international corporations (ÖBB, etc). But they aren’t covered by a DB BahnCard 100.

The trains he mentions are just regular ICEs that operate for some overnight trips.

I can imagine how this can be reasonably comfortable in an older ICE1 in first class, but i wouldn’t want to sleep on ICE4 seats for extended periods of time