The teacher asked him to explain why had he been absent for such a long time.

[Tan Elaine]

The teacher asked him to explain why had he been absent for such a long time.

Should it be he had instead? Thanks.

 

[emsr2d2]

The teacher asked him to explain why had he been absent for such a long time.

Should it be he had instead? Thanks.

You are right. It should be "... to explain why he had been absent ..."