"Hilfs-Ausweis" is an odd term isn't it. I haven't come across it before in relation to the HJ. I'm guessing that it has the same function as the one below as a temporary membership document:
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Or perhaps it was issued to kids to show that they had registered to join the HJ/DJ but had not yet been fully processed. Have you deciphered where he lived? I'm rubbish with sütterlin.
Here's a different type of HJ Hilfsausweis (currently on mil 321):