er weiß nicht, was er

he doesn't know what he

→ er
phrase Rare #33,323
he doesn't know what he This is an incomplete phrase that is followed by a verb, such as sagt (says), tut (does), or tun soll (should do).
GE: Und er weiß nicht, was er tun soll.
EN: And he doesn't know what he should do.

Er weiß nicht, was er da tut!

He doesn't know what he's doing!

Er weiß nicht, was er tut.

He doesn't know what he's doing.

— Schöne Bescherung (1989)

Er weiß nicht, was er redet!

He doesn't know what he's talking about!

— Mad Max: Fury Road (2015)

Er weiß nicht, was er tut, oder?

He doesn't know what he's doing, does he?

— Harry Potter und die Heiligtümer des Todes - Teil 1 (2010)

Er weiß nicht, was er da tut.

He doesn't know what he's doing.

Er hat zu viel getrunken, er weiß nicht, was er sagt.

He drank too much; he doesn’t know what he’s saying.

Er weiß nicht, was er tun soll.

He doesn't know what to do.