DGC and school

[OddballOphelia]

Posting for some advice and support.

I have 2 GC that apparently have never been to school. My DD says she has been homeschooling them but since they came to stay with me, I found out that not to be true. They literally spend all day every day on their ipads. Mostly watching spongebob. They've been here over a month. My DD has not taken them anywhere during that time.

Obviously, I'm very very concerned. They're ages 12 and 8.

How do I even begin to approach this with her? I hesitate to bring up anything with her as she quickly gets defensive and verbally abusive.

Presumably you can tell from interactions with the GC whether they can read appropriately, understand maths, and generally know stuff?

Are they having a holiday whilst with you?

How often do you normally see them? (As in how can this be a surprise?)

If seriously concerned you can report to their local authority.

I've been living overseas so this is the first time seeing them in years due to strict lockdown in the country I used to live.

It was originally a visit but they seemed to have moved in.

How can I assess if they can read, write and do maths? I guess I mean what should they know being 8 and 12? It's been ages since my DC were in school and they all went to school full time.

I've never heard the 8 year old speak. He would hide anytime I would be around but seems to be slowly not doing that anymore.

My driver's license for here had expired and just now got it renewed yesterday so now I can take them out places.

At 12 and 8 they should at least have a rudimentary grasp of basic words (8) and be able to read simple children's books, signs on the road, cereal packets etc..at 12, substantially more, but that's providing they've had an education to do so.
The fact you haven't heard the youngest speak is concerning.. is a selective mutism or does he not have the language skills? I would be gravelly concerned about this.

Buy a board game and see if they can read the rules.
Play Monopoly.
Bake some biscuits with them but want 1.5 times the final amount.
Chat about the Coronation / Climate Change and see what they know.

All sounds very weird.

Chat to 12 yo about their aspirations for the future, eg College / Uni.