The test you're describing sounds more like the WIAT-III than the TOWL-4, if that's most of what he did. In any case, the appropriate prompt to those types of responses is to request that the child write another sentence, using the word in a different (more meaningful) way. If that was not done, then the score is invalid anyway, and any points deducted or not deducted are irrelevant.
Oh interesting. He said he actually asked the tester if he could do that as an answer and she said she could not tell him that. Hmmm, yeah I am not entirely sure it was the TOWL as I was not there. It was a part of a number of writing tasks he had and I know they are giving him the TOWL.
