Forests are good.
Forests with earth trees are especially good, with the best and deepest greens. He can just curl up and be surrounded and safe and alone, and stare up at the leaves.
He doesn't notice anything is wrong until it's about time he should let someone know he's okay--he can't get through to anyone.
It's okay. It's not time to panic yet. Maybe something nearby is blocking the network? Maybe there's someone around he can ask. He can go exploring for a little bit.