Translation:My friend would ask what do I do here.
Would this not be more correct to say ´my friend would ask what i do here´, as you do not need an interrogative order when you are reporting someone else speech even if they asked a question, rendering the extra ´do´ unnecessary and unnatural/ incorrect?
For example, 'what did you do yesterday?'- 'he asked what i did yesterday', not he asked what did i do yesterday.
I agree. By the way, "My friend would ask what I am doing here" (also without an interrogative order) is accepted.
the most likely construction in English would be "my friend would ask what am I doing here"