DH & I have had a little tiff about this today so I'm hoping you'll say I'm right
DS (6) often has to write short sentences in his homework book. We help him by giving him ideas of what to write and I like to leave him to write it himself. If he doesn't know how to spell a word I tell him to sound it out and spell how he thinks it would be whereas DH will tell him he's spelt it wrong & spell the words out for him.
I'm not sure which way the teachers would agree with but feel that DS has to work things out for himself. He is very bright, an excellent reader & more often than not if the spelling is incorrect he has still spelt it in a way that you can work out how he came to it.
You are absolutely correct to let him work it out. This strengthens his neural networks and embeds learning. 'Telling' has no real cognitive value... (and ten to one he'll forget what he was 'told' anyway )
The only 'telling' which might be helpful could be helping with a correct sound spelling if he knows more than one way to spell a particular sound.
That's not what we are asked to do, we were told homework is to be done with a parent not alone, we are told to ask the child how they think a word should be spelt and then to show them the correct way if it is wrong. So all home work handed in should be spelt and punctuated correctly.
The children do loads of work on their own in the class the teacher is well aware of their capabilities. If homework is consistently mis-spelt etc, then they will assume the child is recieving no help at home and you will be asked to come and and chat about why you are not able to support you child at home.
Only have knowledge of ds's school obviously and all above applies only to there.