Selling with unmentioned fault - potential consequences?

[TheOneWiththeNicestSmile]

NB this isn't me (is pestilential offspring )

Item has been listed as needing a battery but in fact has some kind of connection issue. It's not a cheap item either. Offspring is over 21.

Have warned pestilential child that without full disclosure he might end up having to refund in full and not have item returned (or, if he does, will have to pay delivery both ways)

Am I right? He's very resistant to idea that mother knows better than him

Yes you are right. Buyer will more than likely open an item not as described case. eBay will find in their favour, not his.
Are there any bids? If there aren't I'd be revising the listing immediately to make clear that there is a connection issue with the item. If there are bids already I think he might be best to end the listing early on the basis that there was an error in the description. Ending early will result in the automatic cancellation of bids. It may mean there is a fee to pay but it would be better to take the hit on this than to deal with the hassle of the item being not as described.
He should listen to his mum!!!

Remember that it is your account that will be in trouble if there are any SNAD issues with the sale.

Yes, you are right.

I sold an item like this by accident - DH thought it just needed charging but it turned out it was a dead duck. Luckily my buyer was very understanding, went to considerable lengths to get it working with advice from the manufacturer before calling it a day. I gave a full refund, and a grovelling apology. I was lucky - my eBay rating could have been destroyed.

Honesty is always the best policy for eBay item descriptions.

Thank you all for the confirmation

It's his account - he's just set it up & has 0 feedback so maybe nobody will buy it anyway. Nobody had bid yesterday, though he says he has some watchers.

I'll do my best to get him to either change the description or cancel the listing.