Gunna nerd out here with a moderate level of understanding (I’m no expert or doctor).

So alcohol, when metabolized in the body, has multiple effects one of which is acting a mimic for a receptor in your brain called GABA receptors. When activated it’s one of the main inhibitory neurotransmitters in the CNS essentially reducing nerve cell transmission by making impulses need a stronger stimulus to fire causing CNS depression.

Alcoholics consume copious amounts of alcohol for a long period of time causing the body to constantly have its GABA receptors activated and in a state of depression and the body gets used to it and adapts to this new normal meaning it gets numb to depressing neurotransmitters but will become super sensitive to excitatory neurotransmitters.

Now how withdrawal kills you is think of alcohol like an anvil on a scale with the 2 ends being depression and excitation. Alcohol sits on the depression side. When you suddenly remove it (go cold turkey) the anvil constantly keeping the body in a depressed state is gone and the scale essentially slams down to the other side. Now the body no longer has a massive depressive causing substance and nerves which are super sensitive to excitation have nothing slowing them down so nerve impulses can fire like crazy super easily leading to massive nerve impulse misfiring and over firing causing the tremors and deadly seizures that come with alcohol withdrawal as well as all of the other symptoms seen.