Undecided questions
look and tell me the right sentence ,please ^ ^

"Do you know who he is" is correct. You already have a question word order ("do you know"), so the rest of the sentence follows a normal word-order.

"Do you know who is he" sounds like two questions shoved together. It is a common mistake by learners, but not correct at all.

"Do you know who he is?" is better. If you ask directly, then the subject and verb are reversed, such as "Who is he?". That is not the case in your examples. The noun clause "who he is" is the object of the verb "know". The subject and verb are not reversed in that clause because it is no longer a question. Someone is confusing the two cases.