I know different sites have different rules for this, I'm only asking now because this is the first "homework" question I've come across.
Should we allow these types of questions? If so, under what – if any – conditions?
Though, the same standards need to apply - just like any other question on the site. Poorly worded questions, questions that don't fit the standard question criteria, etc should be closed accordingly.
Yes but ...
... we should not solve his assignment for them. We should only point them towards the necessary documentation and give them high-level concept explanations.
After all homework assignments are supposed to make you learn something.