How dangerous is this

The connection to the shutoff switch at the right side was disconnected. No way to shut off the power to both fuses at the same time.

Very dangerous. Obviously 120V are still live when the switch is pulled. Its just plain ugly. I would recommend an electrician for further investigation, improve and or repair as required.

They should switch it out and check that cloth wire.

That switch is broken since it only is opening the pole on the left. IMO it should be replaced before someone gets hurt thinking that the load is actually disconnected with the switch in the OFF position.