If he doesn't feel safe, he should have it changed - simple as that.
It isn't about him feeling unsafe, it's about electrical installation in Poland being unsafe.
Also, young children should be supervised.
Your 'should be' does little to stop fatal accidents. Electrical safety does.
How do you know it is not safe
Because the 'Polish way' is always right, safe electricity in the bathrooms, safe drivers on the roads, safe doctors who are never ever drunk. All those darn statistics must all be wrong.