Irish: Cé hé with indirect relatives and "I don't know" sentences
Normally, a direct relative would be used with "cé hé", but in the following sentence, we need to actually use an indirect relative instead since the preposition air refers back to cé hé, correct?

Níl a fhios agam cé hé ar chuir air cóta.
= I don't know who put a coat on.

Chuir Séan air cóta.
= Shawn put a coat on.

Question

Irish: Cé hé with indirect relatives and "I don't know" sentences
Normally, a direct relative would be used with "cé hé", but in the following sentence, we need to actually use an indirect relative instead since the preposition air refers back to cé hé, correct?

Níl a fhios agam cé hé ar chuir air cóta.
= I don't know who put a coat on.

Chuir Séan air cóta.
= Shawn put a coat on.

Answer

No, you use the direct relative here because "cé hé" still refers to the subject of the verb:

Níl a fhios agam cé hé a chuir cóta air
(Chuir Seán cóta air)
(Note the word order)

You would use the indirect relative in phrases like this, in which "cé" refers to the object of the preposition:

Níl a fhios agam cé ar chuir sé cóta air = I don't know who he put a coat on
(Chuir sé cóta ar Sheán)