Bluewallet lighting balence after channel close?

What happens to lighting ballence in blue wallet if backend channels on umbrel are forced to closed?

Hmm good question.
But let’s say, all your LN channel are closed.
Funds in LNDHUB wallets should still be there.
What are you using from your node is the liquidity and NOT the balance of your channels. These two are different things.
You will still see the balance but you can’t move them out if you do not have liquidity in your node.

So I would just need to open up more channels on the backend? I’m considering setting it up to be the “uncle Jim” node for my family and just want to make sure I don’t loose anyone coin.

Yes. Once your node have the liquidity back (flow of water in your pipes) all those LNDHUB wallets can start making txs.
Read more about this guide I wrote about BW + LNDHUB + Umbrel