As someone who works in and with one, likely not. Languages are inherently physical things, and they need to be passed on in the real world. If the real world still works through [insert regional majority language] that's what's get passed on due to pure economic pressure.

I haven't looked at GPT-4 yet, but for Irish the previous versions were bad. I expect 4 to be bad too simply because most the training data (Irish used online) is quite shit. But I don't see how this really changes anything about the situation on the ground with minority languages and intergenerational transmission.