Hi plyplyppo,
We came across your post and wanted to offer some assistance, when this message is appearing on the device is anything else included in the error message? Sometimes they can give information like if debris or liquid is detected.
Could you also please confirm if this is an official Meta product you are using to charge the Quest 3 or would it be a third party product?
Once we have a bit more information we will be happy to look into this further for you so your son can get back into The Metaverse with no charging worries.
Thank you for your cooperation.