I don't know where he is (indirect questions)
I don't know where he is (indirect questions) means “Indirect questions: inside a bigger sentence, the question word is followed by statement word order”. When a question is built into a longer sentence (after I don't know, Do you know, Can you tell me . Formation: ... question word + subject + verb (statement order)
Indirect questions: inside a bigger sentence, the question word is followed by statement word order
A2Formation
... question word + subject + verb (statement order)
Explanation
When a question is built into a longer sentence (after I don't know, Do you know, Can you tell me ...), keep normal statement order: subject before verb, and no do/does/did. Compare the direct Where is he? with the indirect I don't know where he is. For yes/no questions, join with if or whether: I wonder if it is open. The whole sentence, not the clause, decides the final punctuation.
Examples
Note
So even if the main sentence is a question, the inner clause keeps statement order: Do you know where the station is? (not where is the station).
FAQ
I don't know where he is (indirect questions) — what does it mean and how is it used?
Indirect questions: inside a bigger sentence, the question word is followed by statement word order. When a question is built into a longer sentence (after I don't know, Do you know, Can you tell me ...), keep normal statement order: subject before verb, and no do/does/did. Compare the direct Where is he? with the indirect I don't know where he is. For yes/no questions, join with if or whether: I wonder if it is open. The whole sentence, not the clause, decides the final punctuation.
I don't know where he is (indirect questions) — how do you form it?
... question word + subject + verb (statement order)
I don't know where he is (indirect questions) — any usage notes?
So even if the main sentence is a question, the inner clause keeps statement order: Do you know where the station is? (not where is the station).